Copper-Catalyzed Enantioselective Synthesis of Axially Chiral Allenes
journal contributionposted on 07.12.2012, 00:00 by Hailing Li, Daniel Müller, Laure Guénée, Alexandre Alexakis
A simple copper-catalyzed enantioselective synthesis of axially chiral chloroallenes from the propargylic dichlorides is reported, employing a catalytic amount of easily prepared SimplePhos ligand. Exclusive formation of the desired allenes was observed with good enantioselectivities (ee’s 62–96%). Further transformations to trisubstituted allenes or terminal alkynes with a propargylic quaternary carbon center keep a high level of enantiopurity.