| 1. |
|
|
| 2. |
- Bruneau, Alexandre, et al.
(författare)
-
Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam
- 2017
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 23:52, s. 12886-12891
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, we report on the utilization of a heterogeneous catalyst, consisting of Pd nanoparticles supported on a siliceous mesocellular foam (Pd-0-AmP-MCF), for the synthesis of heterocycles. Reaction of o-iodophenols and protected o-iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2-substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure of the reported Pd nanocatalyst was further elucidated with extended X-ray absorption fine-structure spectroscopy, and it was proven that the catalyst could be recycled multiple times without significant loss of activity.
|
|
| 3. |
|
|
| 4. |
- Deng, Youqian, et al.
(författare)
-
Palladium-Catalyzed Oxidative Carbocyclizations
- 2012
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 18:37, s. 11498-11523
-
Forskningsöversikt (refereegranskat)abstract
- Palladium-catalyzed oxidative carboncarbon bond-forming annulations, that is, carbocyclization reactions, have recently emerged as efficient and atom-economical routes to carbo- and heterocycles, whereby less functionalized substrates and fewer synthetic steps are needed to obtain a target molecule compared with traditional non-oxidative carboncarbon bond-forming reactions. In this review, the synthetic efforts in palladium-catalyzed oxidative carbocyclization reactions are summarized.
|
|
| 5. |
- Gustafson, Karl P. J., et al.
(författare)
-
Chemoenzymatic Dynamic Kinetic Resolution of Primary Benzylic Amines using Pd-0-CalB CLEA as a Biohybrid Catalyst
- 2019
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 25:39, s. 9174-9179
-
Tidskriftsartikel (refereegranskat)abstract
- Herein, we report on the use a biohybrid catalyst consisting of palladium nanoparticles immobilized on cross-linked enzyme aggregates of lipase B of Candida antarctica (CalB CLEA) for the dynamic kinetic resolution (DKR) of benzylic amines. A set of amines were demonstrated to undergo an efficient DKR and the recyclability of the catalysts was studied. Extensive efforts to further elucidate the structure of the catalyst are presented.
|
|
| 6. |
- Gustafson, Karl P. J., et al.
(författare)
-
In Situ Structural Determination of a Homogeneous Ruthenium Racemization Catalyst and Its Activated Intermediates Using X-Ray Absorption Spectroscopy
- 2020
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 26:15, s. 3411-3419
-
Tidskriftsartikel (refereegranskat)abstract
- The activation process of a known Ru-catalyst, dicarbonyl(pentaphenylcyclopentadienyl)ruthenium chloride, has been studied in detail using time resolved in situ X-ray absorption spectroscopy. The data provide bond lengths of the species involved in the process as well as information about bond formation and bond breaking. On addition of potassium tert-butoxide, the catalyst is activated and an alkoxide complex is formed. The catalyst activation proceeds via a key acyl intermediate, which gives rise to a complete structural change in the coordination environment around the Ru atom. The rate of activation for the different catalysts was found to be highly dependent on the electronic properties of the cyclopentadienyl ligand. During catalytic racemization of 1-phenylethanol a fast-dynamic equilibrium was observed.
|
|
| 7. |
- Jiang, Tuo, et al.
(författare)
-
Palladium-Catalyzed Oxidative Carbocyclization/Arylation of Enallenes
- 2011
-
Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 13:21, s. 5838-5841
-
Tidskriftsartikel (refereegranskat)abstract
- A stereoselective palladium-catalyzed oxidative carbocyclization/arylation of enallenes is described. The reaction shows wide tolerance toward highly functionalized arylboronic acids and results In a cis addition of two carbon moieties to an olefin in good to excellent yields.
|
|
| 8. |
- Joosten, Antoine, et al.
(författare)
-
Palladium(II)-Catalyzed Oxidative Cyclization of Allylic Tosylcarbamates : Scope, Derivatization, and Mechanistic Aspects
- 2012
-
Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 18:47, s. 15151-15157
-
Forskningsöversikt (refereegranskat)abstract
- A highly selective oxidative palladium(II)-catalyzed (Wacker-type) cyclization of readily available allylic tosylcarbamates is reported. This operationally simple catalytic reaction furnishes tosyl-protected vinyl-oxazolidinones, common precursors to syn-1,2-amino alcohols, in high yield and excellent diasteroselectivity (>20:1). It is demonstrated that both stoichiometric amounts of benzoquinone (BQ) as well as aerobic reoxidation (molecular oxygen) is suitable for this transformation. The title reaction is shown to proceed through overall trans-amidopalladation of the olefin followed by beta-hydride elimination. This process is scalable and the products are suitable for a range of subsequent transformations such as: kinetic resolution (KR) and oxidative Heck-, Wacker-, and metathesis reactions.
|
|
| 9. |
- Persson, Andreas K. A., 1983-, et al.
(författare)
-
Palladium-Catalyzed Oxidative Borylative Carbocyclization of Enallenes
- 2011
-
Ingår i: Angewandte Chemie International Edition. - : Wiley. - 1433-7851 .- 1521-3773. ; 50:27, s. 6155-6159
-
Tidskriftsartikel (refereegranskat)abstract
- An efficient oxidative carbocyclization/borylation of enallenes uses Pd(OAc)2 as the catalyst, B2pin2 as the boron-transfer reagent, and 1,4-benzoquinone (BQ) as the oxidant (see scheme). The reaction seems to take place through activation of the allene by a PdII complex to give an alkenyl–PdII intermediate followed by carbopalladation of the olefin and subsequent cleavage of the intermediate palladium–carbon bond by the boron reagent.
|
|
| 10. |
- Persson, Andreas K. Å., 1983-, et al.
(författare)
-
Copper-catalyzed N-allenylation of allylic sulfonamides
- 2009
-
Ingår i: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 11:17, s. 3814-3817
-
Tidskriftsartikel (refereegranskat)abstract
- Allylic allenic amides have been synthesized via a copper-catalyzed cross-coupling between allylic sulfonamides and bromoallenes in moderate to good yields. Copper(I) thiophene-2-carboxylate (CuTC) was used a source of copper with DMEDA as the ligand. The allenylated products obtained are potential substrates for palladium-catalyzed carbocyclizations.
|
|
