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A Dearomatization/Debromination Strategy for the [4+1] Spiroannulation of Bromophenols with α,β‐Unsaturated Imines
Author(s) -
Ge Yicong,
Qin Cheng,
Bai Lu,
Hao Jiamao,
Liu Jingjing,
Luan Xinjun
Publication year - 2020
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.202008130
Subject(s) - nucleophile , chemistry , electrophile , catalysis , phenol , domino , combinatorial chemistry , halogen , organic chemistry , medicinal chemistry , alkyl
A novel [4+1] spiroannulation of o ‐ & p ‐bromophenols with α,β‐unsaturated imines has been developed for the direct synthesis of a new family of azaspirocyclic molecules. Notably, several other halophenols (X=Cl, I) were also applicable for this transformation. Moreover, a catalytic asymmetric version of the reaction was realized with 1‐bromo‐2‐naphthols by using a chiral Sc III /Py‐Box catalyst. Mechanistic studies revealed that this domino reaction proceeded through electrophile‐triggered dearomatization of phenol derivatives at their halogenated positions and followed by halogen‐displacement with N ‐nucleophiles via a radical‐based S RN 1 mechanism.