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Nickel(II)‐Catalyzed Asymmetric Propargyl [2,3] Wittig Rearrangement of Oxindole Derivatives: A Chiral Amplification Effect
Author(s) -
Xu Xi,
Zhang Jianlin,
Dong Shunxi,
Lin Lili,
Lin Xiaobin,
Liu Xiaohua,
Feng Xiaoming
Publication year - 2018
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201804080
Subject(s) - oxindole , enantioselective synthesis , chemistry , catalysis , wittig reaction , propargyl , kinetic resolution , stereoselectivity , stereochemistry , medicinal chemistry , organic chemistry
A highly enantioselective [2,3] Wittig rearrangement of oxindole derivatives was realized by using a chiral N , N′ ‐dioxide/Ni II complex as the catalyst under mild reaction conditions. A strong chiral amplification effect was observed, and allowed access to chiral 3‐hydroxy 3‐substituted oxindoles bearing allenyl groups in high yields and enantioselectivities (up to 92 % ee ) by using a ligand with only 15 % ee . A reasonable explanation was given based on the experimental investigations and X‐ray crystal structures of enantiomerically pure and racemic catalysts. Moreover, the first catalytic kinetic resolution of racemic oxindole derivatives by a [2,3] Wittig rearrangement was realized with high efficiency and stereoselectivity.