Pd/PC‐Phos‐Catalyzed Enantioselective Intermolecular Denitrogenative Cyclization of Benzotriazoles with Allenes and N‐Allenamides
作者:Pei‐Chao Zhang、Jie Han、Junliang Zhang
DOI:10.1002/anie.201904805
日期:2019.8.12
Reported herein is an asymmetric Pd/PC‐Phos‐catalyzeddenitrogenativecyclization of benzotriazoles with allenes and N‐allenamides, representing the first example of enantioselectivedenitrogenativecyclizations of benzotriazoles. A series of optically active 3‐methyleneindolines were obtained in good yields with high ee values. The use of inexpensive and readily available starting materials, high
The highly enantioselective copper-catalyzed three-component boroacylation of 1,1-disubstituted allenes is reported by using a class of chiral ligands (WJ-Phos), delivering various functionalized organoboron compounds bearing an all-carbon stereocenter in moderate to good yields with high enantioselectivities. WJ-Phos is a ferrocene-derived chiral sulfinamide phosphine ligand and can be easily synthesized
Arynes, generated in situ from ortho-silylaryl triflates, undergo ene reaction with alkynes possessing propargylic hydrogen in the presence of KF/18-crown-6 in THF at room temperature to give substituted phenylallenes. Various terminal and internal alkynes as well as different arynes can be used to give the corresponding phenylallenes in good to moderate yields. The reaction of alkyne without propargylic
2-Propynylamines from 1,1-Dibromo-1-alkenes Easily accessible 1,1-dibromo-1-alkenes 1 react with primary or secondary amines in a complex series of reactions to give directly N-substituted or N,N-disubstituted (1-Alkyl-1-aryl-2-propynyl)- amines 5 in useful yields. This simple method avoids the isolation of the intermediates (bromoacetylenes or bromoallenes) and makes a series of 2-propynylamines with an acetylenic hydrogen available.
CuH-Catalyzed Regio- and Enantioselective Hydrocarboxylation of Allenes: Toward Carboxylic Acids with Acyclic Quaternary Centers
作者:Sheng Feng、Stephen L. Buchwald
DOI:10.1021/jacs.1c01880
日期:2021.4.7
carboxylic acid derivatives, including those bearing all-carbon quaternary centers, through an enantioselective CuH-catalyzed hydrocarboxylation of allenes with a commercially available fluoroformate. A broad range of heterocycles and functional groups on the allenes were tolerated in this protocol, giving enantioenriched α-quaternary and tertiary carboxylic acid derivatives in good yields with exclusive branched