An Organocatalytic Cope Rearrangement. (16th August 2016)

• Record Type: Journal Article
• Authors: Kaldre, Dainis; Gleason, James L.
• Is Part Of: Angewandte Chemie. Volume 128:Number 38(2016)
• Page Start: 11729
• Page End: 11733
• Publication Date: 2016-08-16
• Subjects: Allylspannung -- Cope-Umlagerung -- Hydrazide -- Iminiumionen -- Organokatalyse; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201606480
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The first example of an organocatalytic Cope rearrangement is reported. Acyclic and cyclic acyl hydrazides catalyze the rearrangement of 1, 5‐hexadiene‐2‐carboxaldehydes via iminium ion formation. A correlation between ring size and catalyst activity was observed for the cyclic hydrazides, with seven‐ and eight‐membered‐ring catalysts being the most active. Diazepane carboxylate5 c (10 mol %) catalyzed the rearrangement of a range of dienes at room temperature in acetonitrile using triflic acid as a co‐catalyst. Preliminary proof of principle for asymmetric catalysis was provided by rearrangement of 3, 3‐dimethyl‐7‐phenyl‐1, 5‐heptadiene‐2‐carboxaldehyde in the presence of a novel 7‐substituted diazepane carboxylate.