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Enantioselective Organocatalytic Construction of Spiroindane Derivatives by Intramolecular Friedel–Crafts‐Type 1,4‐Addition
Author(s) -
Yoshida Keisuke,
Itatsu Yukihiro,
Fujino Yuta,
Inoue Hiroki,
Takao Kenichi
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201601683
Subject(s) - stereocenter , enantioselective synthesis , intramolecular force , friedel–crafts reaction , cinchonidine , chemistry , organocatalysis , catalysis , amine gas treating , organic chemistry , michael reaction
The highly enantioselective organocatalytic construction of spiroindanes containing an all‐carbon quaternary stereocenter by intramolecular Friedel–Crafts‐type 1,4‐addition is described. The reaction was catalyzed by a cinchonidine‐based primary amine and accelerated by water and p ‐bromophenol. A variety of spiro compounds containing quaternary stereocenters were obtained with excellent enantioselectivity (up to 95 % ee ). The reaction was applied to the asymmetric formal synthesis of the spirocyclic natural products (−)‐cannabispirenones A and B.