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Zinc‐Catalyzed Esterification of N ‐β‐Hydroxyethylamides: Removal of Directing Groups under Mild Conditions
Author(s) -
Nishii Yuji,
Hirai Takahiro,
Fernandez Sarah,
Knochel Paul,
Mashima Kazushi
Publication year - 2017
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201700748
Subject(s) - chemistry , amide , catalysis , intramolecular force , zinc , trifluoromethanesulfonate , medicinal chemistry , organic chemistry , reaction conditions , combinatorial chemistry
Amide transformations involving C–N bond cleavage are recognized as difficult reactions owing to the inert nature of amides resulting from resonance. Accordingly, a strong inductive effect and geometrical distortion reasonably decrease the resonance stabilization to attenuate the C–N linkage. Although the conversion of such activated amides has been studied intensively, reaction systems for “unactivated” amides are underdeveloped. We herein report that a zinc(II) trifluoromethanesulfonate [Zn(OTf) 2 ] catalyst achieves the esterification of a wide range of unactivated tertiary amides with the assistance of intramolecular acyl rearrangement. The reaction was applied to the one‐pot removal of various amide‐based directing groups under mild reaction conditions to afford the corresponding esters in high yields.