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Stereoselective Synthesis of Cyclopropylidene Iminolactones and Functionalized Cyclopropanecarboxamides Mediated by Triflic Acid
Author(s) -
Maximiano Adrielle P.,
Sá Marcus M.
Publication year - 2019
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.201900931
Subject(s) - chemistry , triflic acid , intramolecular force , protonation , hydrogenolysis , yield (engineering) , nucleophile , combinatorial chemistry , stereoselectivity , annulation , organic chemistry , medicinal chemistry , catalysis , ion , materials science , metallurgy
A straightforward synthesis of cyclopropylidene iminolactones mediated by triflic acid under mild conditions is described. Different types of hydroxy‐substituted cyclopropanecarboxamides containing a variety of functional groups participated in this smooth cyclization through an intramolecular S N 2 attack of the amidic oxygen on the protonated carbinol group with the release of water. Ten cyclopropylidene iminolactones were readily obtained in high purity after a basic work‐up with no additional chromatographic separation (62–98 % yield). Besides the simplicity, the method is highly diastereoselective and tolerates several functional groups, demonstrating the broad scope of this process. Selected iminolactones were applied in further synthetic transformations to give functionalized cyclopropanecarboxamides through hydrogenolysis or nucleophilic ring‐opening reactions.