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Chiral Zinc(II)‐Catalyzed Enantioselective Tandem α‐Alkenyl Addition/Proton Shift Reaction of Silyl Enol Ethers with Ketimines
Author(s) -
Kang Tengfei,
Cao Weidi,
Hou Liuzhen,
Tang Qiong,
Zou Sijia,
Liu Xiaohua,
Feng Xiaoming
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201810961
Subject(s) - enol , silylation , chemistry , silyl enol ether , catalysis , silyl ether , enantioselective synthesis , medicinal chemistry , organic chemistry
A new catalytic asymmetric tandem α‐alkenyl addition/proton shift reaction of silyl enol ethers with ketimines was serendipitously discovered in the presence of chiral N , N ′‐dioxide/Zn II complexes. The proton shift preferentially proceeded instead of a silyl shift after α‐alkenyl addition of silyl enol ether to the ketimine. A wide range of β‐amino silyl enol ethers were synthesized in high yields with good to excellent ee values. Control experiments suggest that the Mukaiyama–Mannich reaction and tandem α‐alkenyl addition/proton shift reaction are competitive reactions in the current catalytic system. The obtained β‐amino silyl enol ethers were easily transformed into β‐fluoroamines containing two vicinal tetrasubstituted carbon centers.