| 1. |
- Aad, G., et al.
(författare)
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- 2011
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swepub:Mat__t (refereegranskat)
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| 2. |
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| 3. |
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| 4. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 5. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 6. |
- Bixby, H., et al.
(författare)
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Rising rural body-mass index is the main driver of the global obesity epidemic in adults
- 2019
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 569:7755, s. 260-4
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Tidskriftsartikel (refereegranskat)abstract
- Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.
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| 7. |
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| 8. |
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| 9. |
- Jiang, Tuo, et al.
(författare)
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Palladium-Catalyzed Oxidative Synthesis of a-Acetoxylated Enones from Alkynes
- 2016
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 55:19, s. 5824-5828
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Tidskriftsartikel (refereegranskat)abstract
- We report a palladium-catalyzed oxidative functionalization of alkynes to generate -acetoxylated enones in one step. A range of functional groups are well-tolerated in this reaction. Mechanistic studies, including the use of O-18-labeled DMSO, revealed that the ketone oxygen atom in the product originates from DMSO.
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| 10. |
- Jin, Ying-Hui, et al.
(författare)
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Chemoprophylaxis, diagnosis, treatments, and discharge management of COVID-19 : An evidence-based clinical practice guideline (updated version)
- 2020
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Ingår i: Military Medical Research. - : Springer Science and Business Media LLC. - 2054-9369. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the cause of a rapidly spreading illness, coronavirus disease 2019 (COVID-19), affecting more than seventeen million people around the world. Diagnosis and treatment guidelines for clinicians caring for patients are needed. In the early stage, we have issued "A rapid advice guideline for the diagnosis and treatment of 2019 novel coronavirus (2019-nCoV) infected pneumonia (standard version)"; now there are many direct evidences emerged and may change some of previous recommendations and it is ripe for develop an evidence-based guideline. We formed a working group of clinical experts and methodologists. The steering group members proposed 29 questions that are relevant to the management of COVID-19 covering the following areas: chemoprophylaxis, diagnosis, treatments, and discharge management. We searched the literature for direct evidence on the management of COVID-19, and assessed its certainty generated recommendations using the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) approach. Recommendations were either strong or weak, or in the form of ungraded consensus-based statement. Finally, we issued 34 statements. Among them, 6 were strong recommendations for, 14 were weak recommendations for, 3 were weak recommendations against and 11 were ungraded consensus-based statement. They covered topics of chemoprophylaxis (including agents and Traditional Chinese Medicine (TCM) agents), diagnosis (including clinical manifestations, reverse transcription-polymerase chain reaction (RT-PCR), respiratory tract specimens, IgM and IgG antibody tests, chest computed tomography, chest x-ray, and CT features of asymptomatic infections), treatments (including lopinavir-ritonavir, umifenovir, favipiravir, interferon, remdesivir, combination of antiviral drugs, hydroxychloroquine/chloroquine, interleukin-6 inhibitors, interleukin-1 inhibitors, glucocorticoid, qingfei paidu decoction, lianhua qingwen granules/capsules, convalescent plasma, lung transplantation, invasive or noninvasive ventilation, and extracorporeal membrane oxygenation (ECMO)), and discharge management (including discharge criteria and management plan in patients whose RT-PCR retesting shows SARS-CoV-2 positive after discharge). We also created two figures of these recommendations for the implementation purpose. We hope these recommendations can help support healthcare workers caring for COVID-19 patients.
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| 11. |
- Kristan, Matej, et al.
(författare)
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The Visual Object Tracking VOT2013 challenge results
- 2013
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Ingår i: 2013 IEEE INTERNATIONAL CONFERENCE ON COMPUTER VISION WORKSHOPS (ICCVW). - : IEEE. - 9781479930227 ; , s. 98-111
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Konferensbidrag (refereegranskat)abstract
- Visual tracking has attracted a significant attention in the last few decades. The recent surge in the number of publications on tracking-related problems have made it almost impossible to follow the developments in the field. One of the reasons is that there is a lack of commonly accepted annotated data-sets and standardized evaluation protocols that would allow objective comparison of different tracking methods. To address this issue, the Visual Object Tracking (VOT) workshop was organized in conjunction with ICCV2013. Researchers from academia as well as industry were invited to participate in the first VOT2013 challenge which aimed at single-object visual trackers that do not apply pre-learned models of object appearance (model-free). Presented here is the VOT2013 benchmark dataset for evaluation of single-object visual trackers as well as the results obtained by the trackers competing in the challenge. In contrast to related attempts in tracker benchmarking, the dataset is labeled per-frame by visual attributes that indicate occlusion, illumination change, motion change, size change and camera motion, offering a more systematic comparison of the trackers. Furthermore, we have designed an automated system for performing and evaluating the experiments. We present the evaluation protocol of the VOT2013 challenge and the results of a comparison of 27 trackers on the benchmark dataset. The dataset, the evaluation tools and the tracker rankings are publicly available from the challenge website(1).
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| 12. |
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| 13. |
- Lind, Lars, et al.
(författare)
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Heterogeneous contributions of change in population distribution of body mass index to change in obesity and underweight NCD Risk Factor Collaboration (NCD-RisC)
- 2021
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Ingår i: eLife. - : eLife Sciences Publications Ltd. - 2050-084X. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- From 1985 to 2016, the prevalence of underweight decreased, and that of obesity and severe obesity increased, in most regions, with significant variation in the magnitude of these changes across regions. We investigated how much change in mean body mass index (BMI) explains changes in the prevalence of underweight, obesity, and severe obesity in different regions using data from 2896 population-based studies with 187 million participants. Changes in the prevalence of underweight and total obesity, and to a lesser extent severe obesity, are largely driven by shifts in the distribution of BMI, with smaller contributions from changes in the shape of the distribution. In East and Southeast Asia and sub-Saharan Africa, the underweight tail of the BMI distribution was left behind as the distribution shifted. There is a need for policies that address all forms of malnutrition by making healthy foods accessible and affordable, while restricting unhealthy foods through fiscal and regulatory restrictions.
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| 14. |
- Liu, Wei, et al.
(författare)
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A-pi-A structured non-fullerene acceptors for stable organic solar cells with efficiency over 17%
- 2022
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Ingår i: Science in China Series B. - : SCIENCE PRESS. - 1674-7291 .- 1869-1870. ; 65:7, s. 1374-1382
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Tidskriftsartikel (refereegranskat)abstract
- With the development of photovoltaic materials, especially the small molecule acceptors (SMAs), organic solar cells (OSCs) have made breakthroughs in power conversion efficiencies (PCEs). However, the stability of high-performance OSCs remains a critical challenge for future technological applications. To tackle the inherent instability of SMA materials under the ambient conditions, much effort has been made to improve OSCs stability, including device modification and new materials design. Here we proposed a new electron acceptor design strategy and developed a "quasi-macromolecule" (QM) with an A-pi-A structure, where the functionalized pi-bridge is used as a linker between two SMAs (A), to improve the long-term stability without deteriorating device efficiencies. Such type of QMs enables excellent synthetic flexibility to modulate their optical/electro-chemical properties, crystallization and aggregation behaviors by changing the A and pi units. Moreover, QMs possess a unique long conjugated backbone combining high molecular weight over 3.5 kDa with high purity. Compared with the corresponding SMA BTP-4F-OD (Y6-OD), the devices based on newly synthesized A-pi-A type acceptors QM1 and QM2 could exhibit better device stability and more promising PCEs of 17.05% and 16.36%, respectively. This kind of "molecular-framework" (A-pi-A) structure provides a new design strategy for developing high-efficiency and -stability photovoltaic materials.
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| 15. |
- Liu, Wei, et al.
(författare)
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Manipulating molecular aggregation and crystalline behavior of A-DAD-A type acceptors by side chain engineering in organic solar cells
- 2022
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Ingår i: Aggregate. - : Wiley. - 2692-4560. ; 3:3
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Tidskriftsartikel (refereegranskat)abstract
- Alkyl chains engineering plays an important role in photovoltaic materials for organic solar cells. Herein, three A-DAD-A (acceptor-donor-acceptor-donor-acceptor) type acceptors named Y6, Y6-C4, and Y6-C5 with different branching position on the pyrrole motif are discussed and the relationship between molecular aggregation, crystalline, and device performance are systematically investigated. The distance between the branching position and the main backbone affects their optical absorption and energy levels. Y6-C4 and Y6-C5 with the branching position at the fourth and fifth carbon of the alkyl chain show blue-shifted absorption and increased electrochemical bandgaps, compared with Y6 with the branching position at the second carbon of the alkyl side chain. In addition, this distance influences the molecular aggregation and crystalline behavior of the donor/acceptor blends. Compared with Y6-C4, Y6-C5 possesses a stronger crystalline and aggregate ability in the blends with a lower non-radiative energy loss, which results in a higher open circuit voltage (V-oc) of 0.88 V. Finally, Y6-C5-based binary device achieved a high power conversion efficiency up to 16.73% with afill factor (FF) of 0.78. These results demonstrate that the side chain engineering is an effective strategy for tuning the molecular aggregation and crystalline to improve photovoltaic performance of the A-DAD-A type acceptors.
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| 16. |
- Mishra, A, et al.
(författare)
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Diminishing benefits of urban living for children and adolescents' growth and development
- 2023
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 1476-4687 .- 0028-0836. ; 615:7954, s. 874-883
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Tidskriftsartikel (refereegranskat)abstract
- Optimal growth and development in childhood and adolescence is crucial for lifelong health and well-being1–6. Here we used data from 2,325 population-based studies, with measurements of height and weight from 71 million participants, to report the height and body-mass index (BMI) of children and adolescents aged 5–19 years on the basis of rural and urban place of residence in 200 countries and territories from 1990 to 2020. In 1990, children and adolescents residing in cities were taller than their rural counterparts in all but a few high-income countries. By 2020, the urban height advantage became smaller in most countries, and in many high-income western countries it reversed into a small urban-based disadvantage. The exception was for boys in most countries in sub-Saharan Africa and in some countries in Oceania, south Asia and the region of central Asia, Middle East and north Africa. In these countries, successive cohorts of boys from rural places either did not gain height or possibly became shorter, and hence fell further behind their urban peers. The difference between the age-standardized mean BMI of children in urban and rural areas was <1.1 kg m–2 in the vast majority of countries. Within this small range, BMI increased slightly more in cities than in rural areas, except in south Asia, sub-Saharan Africa and some countries in central and eastern Europe. Our results show that in much of the world, the growth and developmental advantages of living in cities have diminished in the twenty-first century, whereas in much of sub-Saharan Africa they have amplified.
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| 17. |
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| 18. |
- Qiu, Youai, et al.
(författare)
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Highly selective olefin-assisted palladium-catalyzed oxidative carbocyclization via remote olefin insertion
- 2017
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Ingår i: Chemical Science. - : Royal Society of Chemistry. - 2041-6520 .- 2041-6539. ; 8:1, s. 616-620
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Tidskriftsartikel (refereegranskat)abstract
- A highly selective olefin-assisted palladium-catalyzed oxidative carbocyclization via remote olefin insertion to afford cyclohexenes has been developed. It was shown that the assisting olefin moiety was indispensable for the formation of the cyclohexene product. Furthermore, preliminary studies on chiral anion-induced asymmetrical carbocyclization-borylation of enallenes have been carried out.
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| 19. |
- Qiu, Youai, et al.
(författare)
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Palladium-Catalyzed Oxidative Carbocyclization–Borylation of Enallenes to Cyclobutenes
- 2016
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 55:22, s. 6520-6524
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Tidskriftsartikel (refereegranskat)abstract
- A highly efficient palladium-catalyzed oxidative borylation of enallenes was developed for the selective formation of cyclobutene derivatives and fully-substituted alkenylboron compounds. Cyclobutenes are formed as the exclusive products in MeOH in the presence of H2O and Et3N, whereas the use of AcOH leads to alkenylboron compounds. Both reactions showed a broad substrate scope and good tolerance for various functional groups, including carboxylic acid ester, free hydroxy, imide, and alkyl groups. Furthermore, transformations of the borylated products were conducted to show their potential applications.
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| 20. |
- Qiu, Youai, et al.
(författare)
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Palladium-Catalyzed Oxidative Cascade Carbonylative Spirolactonization of Enallenols
- 2017
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 56:12, s. 3221-3225
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Tidskriftsartikel (refereegranskat)abstract
- A highly selective palladium-catalyzed oxidative carbonylation/carbocyclization/alkoxycarbonylation of enallenols to afford spirolactones bearing an all-carbon quaternary center was developed. This transformation involves the overall formation of three C-C bonds and one C-O bond through a cascade insertion of carbon monoxide (CO), an olefin, and CO. Preliminary experiments on chiral anion-induced enantioselective carbonylation/carbocyclization of enallenols afforded spirolactones with moderate enantioselectivity.
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| 21. |
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| 22. |
- Song, Jiage, et al.
(författare)
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Over 13% Efficient Organic Solar Cells Based on Low-Cost Pentacyclic A-DA D-A-Type Nonfullerene Acceptor
- 2021
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Ingår i: Solar RRL. - : Wiley-Blackwell. - 2367-198X. ; 5:8
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Tidskriftsartikel (refereegranskat)abstract
- Recent studies have almost focused on finding active layer materials with extended pi-conjugation structures for high-performance organic solar cells (OSCs). However, with the extension of conjugate length, the synthesis difficulty and cost of materials will increase. Achieving high efficiency while reducing material costs is a prerequisite for the commercialization of OSCs. Herein, two low-cost A-DA D-A-type (where A and D represent an electron-withdrawing unit and an electron-donating unit, respectively) nonfullerene acceptors (Y25,Y26) are synthesized with pentacyclic fused backbone as the DA D electron-deficient core and 5,6-difluoro-3-(dicyandiamethyl) indigo as the end groups. Compared with classical Y series acceptors with heptacyclic backbone, although Y25 and Y26 own the reduced conjugated length, they still show moderate performance (11.65% and 13.34%), and the cost of synthesis is significantly reduced. Therefore, we provide a new molecular design idea for commercially efficient nonfullerene OSCs acceptors. We also find that adding alkyl chains to the beta site of thiophenes is beneficial to obtaining the reduced energetic disorder, dominant molecular stacking, and desirable morphology, which can facilitate charge carrier transport and prompt higher short-circuit current density (J(sc)) as well as fill factor.
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| 23. |
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| 24. |
- Yang, Bin, et al.
(författare)
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Enzyme- and Ruthenium-Catalyzed Enantioselective Transformation of alpha-Allenic Alcohols into 2,3-Dihydrofurans
- 2016
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 55:18, s. 5568-5572
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Tidskriftsartikel (refereegranskat)abstract
- An efficient one-pot method for the enzyme- and ruthenium-catalyzed enantioselective transformation of alpha-allenic alcohols into 2,3-dihydrofurans has been developed. The method involves an enzymatic kinetic resolution and a subsequent ruthenium-catalyzed cycloisomerization, which provides 2,3-dihydrofurans with excellent enantioselectivity (up to >99%ee). A ruthenium carbene species was proposed as a key intermediate in the cycloisomerization.
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| 25. |
- Yuan, Jun, et al.
(författare)
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Understanding energetic disorder in electron-deficient-core-based non-fullerene solar cells
- 2020
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Ingår i: Science in China Series B. - : SCIENCE PRESS. - 1674-7291 .- 1869-1870. ; 63:8, s. 1159-1168
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Tidskriftsartikel (refereegranskat)abstract
- Recent advances in material design for organic solar cells (OSCs) are primarily focused on developing near-infrared non-fullerene acceptors, typically A-DA D-A type acceptors (where A abbreviates an electron-withdrawing moiety and D, an electron-donor moiety), to achieve high external quantum efficiency while maintaining low voltage loss. However, the charge transport is still constrained by unfavorable molecular conformations, resulting in high energetic disorder and limiting the device performance. Here, a facile design strategy is reported by introducing the "wing" (alkyl chains) at the terminal of the DA D central core of the A-DA D-A type acceptor to achieve a favorable and ordered molecular orientation and therefore facilitate charge carrier transport. Benefitting from the reduced disorder, the electron mobilities could be significantly enhanced for the "wing"-containing molecules. By carefully changing the length of alkyl chains, the mobility of acceptor has been tuned to match with that of donor, leading to a minimized charge imbalance factor and a high fill factor (FF). We further provide useful design strategies for highly efficient OSCs with high FF.
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| 26. |
- Zhang, Jun, et al.
(författare)
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Stereochemical editing : Catalytic racemization of secondary alcohols and amines
- 2024
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Ingår i: Chinese Chemical Letters. - 1001-8417 .- 1878-5964. ; 35:5
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Tidskriftsartikel (refereegranskat)abstract
- Chiral alcohols and amines are important structural units widely existing in pharmaceuticals, agrochemicals, and food additives. Dynamic kinetic resolution (DKR) is an efficient strategy to deliver optically active alcohols and amines from their racemates. For the development of DKR method, racemization catalyst plays as a crucial element with the requirement of compatibility with the kinetic resolution (KR) system. In this paper, recent advance in the catalytic racemization of secondary alcohols and amines is summarized based on different types of racemizing intermediates, which are redox racemization via ketone/imine intermediates, racemization via radical intermediates, and racemization via carbocation intermediates. Enzymatic racemization of secondary alcohols and amines is also enclosed. (c) 2024 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.
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| 27. |
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| 28. |
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| 29. |
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| 30. |
- Zhu, Can, et al.
(författare)
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An Efficient Approach to Regio- and Stereodefined Fully-Substituted Alkenylsilanes by Pd-Catalyzed Allenic C(sp(3))-H Oxidation
- 2019
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Ingår i: Chemistry: A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 25:49, s. 11566-11573
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Tidskriftsartikel (refereegranskat)abstract
- A highly efficient palladium-catalyzed functionalization of allenylsilanes to give regio- and stereodefined fully-substituted alkenylsilanes has been developed. This oxidative coupling reaction showed good functional group compatibility with exclusive regio- and stereoselectivity. The pending olefin on the silyl group was shown to be an indispensable element for the initial allenic C(sp(3))-H bond cleavage, and performs as the directing group to control the overall selectivity. The addition of substoichiometric amounts of Et3N was found to increase the reaction rate leading to a higher reaction yield. The reaction can be easily scaled up and applied for the late-stage functionalization of natural products and pharmaceutical compounds, including amino acids and steroid derivatives. The newly introduced functional groups include aryl, alkynyl, and boryl groups. The highly strained four-membered ring, silacyclobutene was obtained when B(2)pin(2) was employed as the coupling partner. Mechanistic studies, including kinetic isotope effects, showed that the allenic C(sp(3))-H bond cleavage is the rate-limiting step.
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| 31. |
- Zhu, Can, et al.
(författare)
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Efficient Stereoselective Carbocyclization to cis-1,4-Disubstituted Heterocycles Enabled by Dual Pd/Electron Transfer Mediator (ETM) Catalysis
- 2020
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 142:12, s. 5751-5759
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Tidskriftsartikel (refereegranskat)abstract
- An efficient Pd/ETM (ETM = electron transfer mediator)-cocatalyzed stereoselective oxidative carbocyclization of dienallenes under aerobic oxidation conditions has been developed to afford six-membered heterocycles. The use of a bifunctional cobalt complex [Co(salophen)-HQ] as hybrid ETM gave a faster aerobic oxidation than the use of separated ETMs, indicating that intramolecular electron transfer between the hydroquinone unit and the oxidized metal macrocycle occurs. In this way, a class of important cis-1,4-disubstituted six-membered heterocycles, including dihydropyran and tetrahydropyridine derivatives were obtained in high diastereoselectivity with good functional group compatibility. The experimental and computational (DFT) studies reveal that the pendent olefin does not only act as an indispensable element for the initial allene attack involving allenic C(sp(3))-H bond cleavage, but it also induces a face-selective reaction of the olefin of the allylic group, leading to a highly diastereoselective formation of the product. Finally, the deuterium kinetic isotope effects measured suggest that the initial allenic C(sp(3))-H bond cleavage is the rate-limiting step, which was supported by DFT calculations.
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| 32. |
- Zhu, Can, et al.
(författare)
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Highly Selective Cascade C-C Bond Formation via Palladium-Catalyzed Oxidative Carbonylation-Carbocyclization-Carbonylation-Alkynylation of Enallenes
- 2015
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 137:37, s. 11868-11871
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Tidskriftsartikel (refereegranskat)abstract
- A highly efficient palladium-catalyzed oxidative cascade reaction of enallenes undergoing overall four C-C bond formations has been developed. The insertion cascade proceeds via carbonylation carbocyclization carbonylation alkynylation involving sequential insertion of carbon monoxide, olefin, and carbon monoxide. Furthermore, different types of terminal alkynes and functionalized enallenes have been investigated and found to undergo the cascade reaction under mild reaction conditions.
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| 33. |
- Zhu, Can, et al.
(författare)
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Highly Selective Construction of Seven-Membered Carbocycles by Olefin-Assisted Palladium-Catalyzed Oxidative Carbocyclization-Alkoxycarbonylation of Bisallenes
- 2016
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Ingår i: Angewandte Chemie International Edition. - : Wiley-VCH Verlagsgesellschaft. - 1433-7851 .- 1521-3773. ; 55:46, s. 14405-14408
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Tidskriftsartikel (refereegranskat)abstract
- An olefin-assisted palladium-catalyzed oxidative carbocyclization-alkoxycarbonylation of bisallenes to afford seven-membered carbocycles has been established. This dehydrogenative coupling reaction showed excellent substrate scope and functional group compatibility. The reaction exhibited high chemo-and regioselectivity, and ester 3 was the only product obtained. The olefin unit has been proven to be indispensable during the reaction. Moreover, intramolecular oxidative coupling suggests that the reaction proceeds via a (pallyl)palladium intermediate.
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| 34. |
- Zhu, Can, et al.
(författare)
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Highly Selective Palladium-Catalyzed Hydroborylative Carbocyclization of Bisallenes to Seven-Membered Rings
- 2018
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 140:43, s. 14324-14333
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Tidskriftsartikel (refereegranskat)abstract
- A highly selective palladium-catalyzed hydroborylative carbocyclization of bisallenes to afford seven-membered rings has been established. This ring-closing coupling reaction showed good functional group compatibility with high chemo- and regioselectivity, as seven-membered ring 3 was the only product obtained. The extensive use of different linkers, including nitrogen, oxygen, malononitrile, and malonate, showed a broad substrate scope for this approach. A one-pot cascade reaction was realized by trapping the primary allylboron compound with an aldehyde, affording a diastereomerically pure alcohol and a quaternary carbon center by formation of a new C-C bond. A comprehensive mechanistic DFT investigation is also presented. The calculations suggest that the reaction proceeds via a concerted hydropalladation pathway from a Pd(0)-olefin complex rather than via a pathway involving a defined palladium hydride species. The reaction was significantly accelerated by the coordination of the pendant olefin, as well as the introduction of suitable substituents in the bridge, due to the Thorpe-Ingold effect.
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| 35. |
- Zhu, Can, et al.
(författare)
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Olefin-Directed Palladium-Catalyzed Regio- and Stereoselective Hydroboration of Allenes
- 2016
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Ingår i: Chemistry - A European Journal. - : Wiley-VCH Verlagsgesellschaft. - 0947-6539 .- 1521-3765. ; 22:9, s. 2939-2943
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Tidskriftsartikel (refereegranskat)abstract
- An olefin-directed palladium-catalyzed regio- and stereoselective hydroboration of allenes has been developed to afford fully substituted alkenylboron compounds. The reaction showed a broad substrate scope: a number of functionalized allenes, including 2,3-dienoate, 3,4-dienoate, 3,4-dienol, 1,2-allenylphosphonate, and alkyl-substituted allenes, could be used in this olefin-directed allene hydroboration. The olefin unit was proven to be an indispensable element for this transformation.
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| 36. |
- Zhu, Can, et al.
(författare)
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Olefin-Directed Palladium-Catalyzed Regio- and Stereoselective Oxidative Arylation of Allenes
- 2015
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Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 54:31, s. 9066-9069
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Tidskriftsartikel (refereegranskat)abstract
- An olefin-directed palladium-catalyzed oxidative regio- and stereoselective arylation of allenes to afford 1,3,6-trienes has been established. A number of functionalized allenes, including 2,3- and 3,4-dienoates and 3,4-dienol derivatives, have been investigated and found to undergo the olefin-directed allene arylation. The olefin moiety has been proven to be a crucial element for the arylating transformation.
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| 37. |
- Zhu, Can, et al.
(författare)
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Palladium-catalyzed oxidative dehydrogenative carbonylation reactions using carbon monoxide and mechanistic overviews
- 2020
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Ingår i: Chemical Society Reviews. - : Royal Society of Chemistry. - 0306-0012 .- 1460-4744. ; 49, s. 341-353
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Tidskriftsartikel (refereegranskat)abstract
- Carbon monoxide, which is an abundant and inexpensive carbonyl source, has been widely applied to synthesize carbonyl-containing compounds, for example ketones, esters, and amides. These types of compounds are ubiquitous in natural products, pharmaceuticals, as well as in functional materials. This review focuses on the palladium-catalyzed dehydrogenative C-H/X-H (X = C, N, O) carbonylation transformations under oxidative conditions. The related C-H bonds here include C(sp)-H, C(sp2)-H, and C(sp3)-H bonds. From a step- and atom-economy perspective, transition metal-catalyzed oxidative dehydrogenative C-H/X-H carbonylation reactions with CO constitute one of the most efficient strategies for the construction of versatile carbonyl groups, without the requirement of pre-functionalized substrates.
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| 38. |
- Zhu, Can, et al.
(författare)
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Tuning the electron-deficient core of a non-fullerene acceptor to achieve over 17% efficiency in a single-junction organic solar cell
- 2020
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Ingår i: Energy & Environmental Science. - : ROYAL SOC CHEMISTRY. - 1754-5692 .- 1754-5706. ; 13:8, s. 2459-2466
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Tidskriftsartikel (refereegranskat)abstract
- Finding effective molecular design strategies to enable efficient charge generation and small energy loss is among the long-standing challenges in developing high performance non-fullerene organic solar cells (OSCs). Recently, we reported Y-series non-fullerene acceptors with an electron-deficient-core-based fused structure (typically Y6), opening a new door to achieve high external quantum efficiency (∼80%) while maintaining low energy loss (∼0.57 eV). On this basis, further reducing the energy losses and ultimately improving the performance of OSCs has become a research hotspot. In this paper, we design and synthesize a new member of the Y-series acceptor family, Y18, which adopts a fused benzotriazole segment with unique luminescence properties as its electron-deficient core. Compared to Y6, the benzotriazole-based acceptor Y18 exhibits extended optical absorption and higher voltage. Consequently, the device delivers a promising power conversion efficiency of 16.52% with a very low energy loss of 0.53 eV. Further device optimization by exploiting a ternary blend strategy allowed us to achieve a high efficiency of 17.11% (certified as 16.76% by NREL). Y18 may become one of the most important candidate materials for its broader absorption spectra and higher voltage of Y18 (compared to Y6) in the OSCs field.
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