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Amine‐Urea‐Mediated Asymmetric Cycloadditions between Nitrile Oxides and o ‐Hydroxystyrenes by Dual Activation
Author(s) -
Suga Hiroyuki,
Hashimoto Yohei,
Toda Yasunori,
Fukushima Kazuaki,
Esaki Hiroyoshi,
Kikuchi Ayaka
Publication year - 2017
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201705662
Subject(s) - nitrile , chemistry , enantioselective synthesis , bifunctional , amine gas treating , cinchona , brønsted–lowry acid–base theory , catalysis , cycloaddition , homo/lumo , hydrogen bond , organic chemistry , combinatorial chemistry , photochemistry , molecule
The first example of asymmetric 1,3‐dipolar cycloadditions between nitrile oxides and o ‐hydroxystyrenes, mediated by cinchona‐alkaloid‐based amine‐ureas is reported. The method is based on a dual activation involving both LUMO and HOMO activations. In addition to the stoichiometric asymmetric induction, a catalytic amount of amine‐urea enables the cycloadditions to proceed in an enantioselective manner. Computational studies strongly support the HOMO activation of o ‐hydroxystyrenes and LUMO activation of nitrile oxides by hydrogen‐bonding interactions with the Brønsted acid/base bifunctional catalyst.