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Asymmetric Hydrogenation of Ketones and Enones with Chiral Lewis Base Derived Frustrated Lewis Pairs
Author(s) -
Gao Bochao,
Feng Xiangqing,
Meng Wei,
Du Haifeng
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201914568
Subject(s) - frustrated lewis pair , lewis acids and bases , chemistry , oxazoline , asymmetric hydrogenation , boranes , boron , enantioselective synthesis , combinatorial chemistry , organic chemistry , catalysis
Abstract The concept of frustrated Lewis pairs (FLPs) has been widely applied in various research areas, and metal‐free hydrogenation undoubtedly belongs to the most significant and successful ones. In the past decade, great efforts have been devoted to the synthesis of chiral boron Lewis acids. In a sharp contrast, chiral Lewis base derived FLPs have rarely been disclosed for the asymmetric hydrogenation. In this work, a novel type of chiral FLP was developed by simple combination of chiral oxazoline Lewis bases with achiral boron Lewis acids, thus providing a promising new direction for the development of chiral FLPs in the future. These chiral FLPs proved to be highly effective for the asymmetric hydrogenation of ketones, enones, and chromones, giving the corresponding products in high yields with up to 95 % ee . Mechanistic studies suggest that the hydrogen transfer to simple ketones likely proceeds in a concerted manner.