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Enantioselective N‐Heterocyclic Carbene Catalysis by the Umpolung of α,β‐Unsaturated Ketones
Author(s) -
Nakano Yuji,
Lupton David W.
Publication year - 2016
Publication title -
angewandte chemie
Language(s) - English
Resource type - Journals
eISSN - 1521-3757
pISSN - 0044-8249
DOI - 10.1002/ange.201510106
Subject(s) - umpolung , enantioselective synthesis , carbene , chemistry , catalysis , protonation , organocatalysis , propionates , aryl , organic chemistry , medicinal chemistry , combinatorial chemistry , alkyl , nucleophile , ion
N‐Heterocyclic carbene‐catalyzed formation of β‐anionic intermediates from enones has been employed in the enantioselective synthesis of 2‐aryl propionates. The reaction was achievable using a homochiral 4‐MeOC 6 H 4 morpholinone catalyst allowing the first example of enantioselective catalysis by umpolung of α,β‐unsaturated ketones. The reaction is high yielding, and shows robustness with reasonable generality. A mechanism is proposed in which the enantiodetermining protonation is achieved using either hexafluoroisopropanol or the formed naphthol product.