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Updated: Jul 4, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
A general organocatalytic enantioselective malonate addition to alpha,beta-unsaturated enones
Veit Wascholowski1, Kristian Rahbek Knudsen, Claire E T Mitchell
1Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, UK.
Abstract:
A general enantioselective organocatalytic conjugate addition procedure of a variety of malonates to alpha,beta-unsaturated enone systems is presented. The reaction is efficiently catalysed by the pyrrolidinyl tetrazole catalyst 1. Cyclic, acyclic and aromatic enones can be used and the reaction with ethyl malonates 3 b provides the Michael addition products in high yields with good to excellent enantioselectivities. Since only 1.5 equivalents of malonate are used as a reagent, the reaction is readily scaled and practical to operate. Furthermore, the malonate addition products can be easily mono decarboxylated without loss in enantiomeric excess by enzymatic or sodium hydroxide mediated methods.
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