Nickel-Catalyzed Arylboration of Alkenylarenes: Synthesis of Boron-Substituted Quaternary Carbons and Regiodivergent Reactions
作者:Liang-An Chen、Alan R. Lear、Pin Gao、M. Kevin Brown
DOI:10.1002/anie.201904861
日期:2019.8.5
A method for the construction of boron‐substituted quaternary carbons or diarylquaternary carbons by arylboration of highly substituted alkenylarenes is presented. A wide range of alkenes and arylbromides can participate in this reaction thus allowing for a diverse assortment of products to be prepared. In addition, a solvent dependent regiodivergent arylboration of 1,2‐disubstituted alkenylarenes
Diastereomerically and Enantiomerically Pure 2,3-Disubstituted Pyrrolidines from 2,3-Aziridin-1-ols Using a Sulfoxonium Ylide: A One-Carbon Homologative Relay Ring Expansion
作者:Jennifer M. Schomaker、Somnath Bhattacharjee、Jun Yan、Babak Borhan
DOI:10.1021/ja065833p
日期:2007.2.1
An ylide-based aza-Payne rearrangement of 2,3-aziridin-1-ols leads to an efficient process for the preparation of pyrrolidines. The aza-Payne rearrangement under basic reaction conditions favors the formation of epoxy amines. Subsequent nucleophilic attack of the epoxide by the ylide yields a bis-anion, which upon a 5-exo-tet ring-closure yields the desired pyrrolidine, thus completing the relay of
Highly enantioselective hydrogenation of a variety of 2-substituted-2-alkenols has been achieved using a ChenPhosâRh complex as catalyst, giving â¥99% ee for most substrates. Optically active antifungal agent amorolfine was first synthesised using hydrogenation as the key step.
Vanadium-Catalyzed Asymmetric Epoxidation of Allylic Alcohols in Water
作者:Andrei V. Malkov、Louise Czemerys、Denis A. Malyshev
DOI:10.1021/jo900294h
日期:2009.5.1
Asymmetric V-catalyzed epoxidation of allylic alcohols can be carried out in water with chiral ligands, which incorporate sulfonamide and hydroxamic acid fragments. Furthermore, the reaction, notorious for its ligand-deceleration effect, in water turned into the ligand-accelerated process. By using this aqueous protocol, a range of allylic alcohols were epoxidized with up to 94% ee.
Selective construction of quaternary stereocentres in radical cyclisation cascades triggered by electron-transfer reduction of amide-type carbonyls
作者:Huan-Ming Huang、Pablo Bonilla、David J. Procter
DOI:10.1039/c7ob00739f
日期:——
Radical cyclisation cascades triggered by electron-transfer to amide-type carbonyls using SmI2–H2O–LiBr, result in the selective construction of quaternary carbon stereocentres.