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Chemoselective Borane‐Catalyzed Hydroarylation of 1,3‐Dienes with Phenols
Author(s) -
Wang Guoqiang,
Gao Liuzhou,
Chen Hui,
Liu Xueting,
Cao Jia,
Chen Shengda,
Cheng Xu,
Li Shuhua
Publication year - 2019
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201811729
Subject(s) - carbocation , chemistry , phenols , borane , catalysis , protonation , friedel–crafts reaction , counterion , organic chemistry , medicinal chemistry , ion
A B(C 6 F 5 ) 3 ‐catalyzed hydroarylation of a series of 1,3‐dienes with various phenols has been established through a combination of theoretical and experimental investigations, affording structurally diverse ortho ‐allyl phenols. DFT calculations show that the reaction proceeds through a borane‐promoted protonation/Friedel–Crafts pathway involving a π‐complex of a carbocation–anion contact ion pair. This protocol features simple and mild reaction conditions, broad functional‐group tolerance, and low catalyst loading. The obtained ortho ‐allyl phenols could be further converted into flavan derivatives using B(C 6 F 5 ) 3 with good cis diastereoselectivity. Furthermore, this transformation was applied in the late‐stage modification of pharmaceutical compounds.