Premium
Asymmetric Synthesis of Fluorinated Allenes by Rhodium‐Catalyzed Enantioselective Alkylation/Defluorination of Propargyl Difluorides with Alkylzincs
Author(s) -
Ng Jia Sheng,
Hayashi Tamio
Publication year - 2021
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202109290
Subject(s) - chemistry , enantioselective synthesis , rhodium , regioselectivity , propargyl , difluoride , catalysis , medicinal chemistry , alkylation , triple bond , catalytic cycle , organic chemistry , double bond
The reaction of propargyl difluorides R 1 CF 2 C≡CR 2 with alkylzincs R 3 ZnCl giving axially chiral fluorinated allenes R 1 FC=C=CR 2 R 3 with high enantioselectivity (up to 99 % ee ) was found to be catalyzed by a chiral diene/rhodium complex. A key step in the catalytic cycle is selective elimination of one of the enantiotopic fluorides at the β‐position of an alkenyl‐Rh intermediate, which is generated by regioselective addition of R 3 ‐Rh onto the triple bond of the starting difluorides.