| 1. |
- Borg, Tessie, et al.
(författare)
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Diastereoselective formation of 2,3,4,5-tetrasubstituted tetrahydrofurans by a Lewis acid promoted addition of C3-substituted 1,3-bis(silyl)propenes to aldehydes
- 2013
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Ingår i: Tetrahedron Letters. - : Pergamon Press. - 0040-4039 .- 1359-8562. ; 54:30, s. 3916-3918
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Tidskriftsartikel (refereegranskat)abstract
- A mild, efficient, Lewis acid promoted addition of C3-substituted 1,3-bis(silyl)propenes to aldehydes to provide the corresponding 2,3,4,5-tetrasubstituted tetrahydrofurans in excellent stereoselectivity is reported.
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| 2. |
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| 3. |
- Borg, Tessie, et al.
(författare)
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Diastereoselective Nucleophilic Addition to Aldehydes with Polar alpha- and alpha,beta-Substituents
- 2011
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Ingår i: Advanced Synthesis and Catalysis. - : Wiley. - 1615-4150 .- 1615-4169. ; 353:11-12, s. 2022-2036
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Tidskriftsartikel (refereegranskat)abstract
- The stereoselectivities obtained in Lewis acid-promoted Mukaiyama aldol additions and Sakurai allylations of mono-, and syn- and anti-disubstituted aldehydes possessing various polar alpha- and beta-substituents under non-chelating conditions are presented. The stereochemical outcome in the nucleophilic addition to alpha-substituted aldehydes containing an alpha-benzyloxy, alpha-fluoro or alpha-sulfonamide substituent are accurately predicted by current stereoinduction models. In contrast, the selectivitites obtained from addition of sterically demanding nucleophiles to alpha-chloro-substituted aldehydes cannot be rationalized by the same models and an alternative is discussed. The stereochemichal outcome in the additions to alpha, beta-disubstituted aldehydes is more complex and cannot be predicted using current models.
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| 4. |
- Borg, Tessie, et al.
(författare)
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Lewis Acid-Promoted Addition of 1,3-Bis(silyl)propenes to Aldehydes : A Route to 1,3-Dienes
- 2011
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Ingår i: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 76:19, s. 8070-8075
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Tidskriftsartikel (refereegranskat)abstract
- The Lewis acid-promoted addition of 1,3-bis(silyl)-propenes to aldehydes to provide the corresponding (E)-1,3-dienes in excellent stereoselectivity and good to excellent yields is reported. The procedure is mild, base-free, and operationally straightforward.
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| 5. |
- Borg, Tessie, et al.
(författare)
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Mukaiyama aldol addition to α-chloro-substituted aldehydes. Origin of the unexpected syn selectivity.
- 2010
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Ingår i: Chemical Communications. - : Royal Society of Chemistry (RSC). - 1359-7345 .- 1364-548X. ; 46:8, s. 1281-1283
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Tidskriftsartikel (refereegranskat)abstract
- The addition of sterically demanding enolsilanes to alpha-chloro aldehydes results unexpectedly in preferential formation of the anti-PFA product (1,2-syn), while the addition of the corresponding boron enolate furnishes the expected polar Felkin-Anh product (1,2-anti). A stereoinduction model explaining these observations is proposed.
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| 6. |
- Danielsson, Jakob, et al.
(författare)
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1,3-Dipolar Cycloaddition of Azomethine Ylides to Aldehydes : Synthesis of anti alpha-Amino-beta-Hydroxy Esters
- 2011
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :3, s. 607-613
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Tidskriftsartikel (refereegranskat)abstract
- A 1,3-dipolar cycloaddition reaction of azomethine ylides to aldehydes is described. The azomethine ylides, generated by thermal electrocyclic ring opening of aziridines, adds to aldehydes in good yields with moderate to good selectivities to furnish oxazolidines. The oxazolidines were subsequently hydrolyzed to the corresponding amino alcohols, giving the anti diastereomer as the major product.
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| 7. |
- Danielsson, Jakob, 1985-
(författare)
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Stereoselective Nucleophilic Additions to Aldehydes and Synthesis of α-Amino-β- Hydroxy-Esters
- 2012
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis deals with the development of new reaction methodology as well as stereochemical investigations. The first part concerns the investigation of 1,2- and merged 1,2- and 1,3- asymmetric induction in Mukaiyama aldol additions to α-heteroatom and α,β- heteroatom substituted aldehydes respectively. In particular, the unexpected 1,2-syn selectivity obtained in the addition of sterically hindered nucleophiles to α-chloroaldehydes is examined, and an explanation for the observed stereochemical trends is proposed. The second part describes the development of a novel entry to α-amino-β- hydroxy esters by a 1,3-dipolar cycloaddition reaction of aldehydes and azomethine ylides, generated by thermolysis of aziridines. The third part deals with our efforts to develop a novel entry to vicinal all- carbon quaternary centers, based on an intramolecular domino Heck- carbonylation reaction using tetrasubstituted olefins.
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| 8. |
- Danielsson, Jakob, et al.
(författare)
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Studies Toward Communesin F: A Diels-Alder Approach.
- 2014
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Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7052 .- 1523-7060. ; 16:3, s. 784-787
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Tidskriftsartikel (refereegranskat)abstract
- A Diels-Alder reaction is used as a key step in a synthetic study toward communesin F, in order to simultaneously introduce both of the all-carbon quaternary stereocenters with complete control of relative stereochemistry. Further manipulations of the cycloadduct, toward the hexacyclic core-structure of communesin F, are also disclosed.
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| 9. |
- Seashore-Ludlow, Brinton, et al.
(författare)
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1,3-Bis(silyl)propenes
- 2011
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Ingår i: E-EROS ENCYCLOPEDIA OF REAGENTS FOR ORGANIC SYNTHESIS. - : John Wiley & Sons.
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Forskningsöversikt (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Seashore-Ludlow, Brinton, et al.
(författare)
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Addition of Azomethine Ylides to Aldehydes : Mechanistic Dichotomy of Differentially Substituted alpha-Imino Esters
- 2010
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Ingår i: European Journal of Organic Chemistry. - : Wiley. - 1434-193X .- 1099-0690. ; :20, s. 3927-3933
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Tidskriftsartikel (refereegranskat)abstract
- The formal 1,3-dipolar cycloaddition of azomethine ylides and aldehydes is explored, as hydrolysis of the resulting oxazolidine product gives facile access to valuable syn-beta-aryl-beta-hydroxy-alpha-amino esters. The use of using benzaldehyde-derived imines as the ylide precursor results in 1,3-dipolar cycloaddition with high conversions but low diastereoselectivity. In contrast, the employment of benzophenone-derived imines as the ylide precursor results in an aldol reaction, which gives the intermediate oxazolidine in high diastereoselectivity and requires a weak acid catalyst to achieve higher conversions.
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