Enantioselective Catalytic Asymmetric A3 Coupling with Phosphino-Imidazoline Ligands
作者:Balaji V. Rokade、Patrick J. Guiry
DOI:10.1021/acs.joc.9b00728
日期:2019.5.3
A practical application of the UCD-PHIM ligand in the copper-catalyzed asymmetric A3 coupling is reported for aromatic, alkenylic, and alkynylic aldehydes under mild reaction conditions, low catalytic loading, and at ambient temperature. A broad range of aldehydes, secondary amines with a cheaper ethyne equivalent, 2-methyl-3-butyn-2-ol, was explored and enantioselectivities of up to 99% ee were obtained
An easily removable stereo-dictating group for enantioselective synthesis of propargylic amines
作者:Wu Fan、Shengming Ma
DOI:10.1039/c3cc45118f
日期:——
We report herein a CuBr-catalyzed three-component coupling of 2-methylbut-3-yn-2-ol, aldehydes and pyrrolidine or 1,2,3,4-tetrahydroisoquinoline leading to the corresponding chiral propargylamines in excellent enantiomeric excess (91 to >99% ee) and high yields (79–95% yield). The dimethylcarbinol unit in 2-methylbut-3-yn-2-ol, which may be easily removed at the later stage to regenerate a terminal alkyne unit for further elaboration, plays a very important role in ensuring high enantioselectivity. This protocol provides easy and very general access to different terminal and non-terminal tertiary propargylic amines.