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Updated: Aug 4, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Three-component, room temperature crotylation catalyzed by solid-supported Brønsted acid: enantioselective synthesis
Darren J Lipomi1, James S Panek
1Department of Chemistry and Center for Chemical Methodology and Library Development, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA.
Abstract:
[reaction: see text] A heterogeneous, three-component crotylation of in situ generated N-acyl iminium ions has been developed. This reaction proceeds under ambient temperature in MeCN and is catalyzed by macroporous polystyrene-bound sulfonic acid (MP-TsOH). Workup is accomplished by filtration, upon which the catalyst is recoverable. A range of homoallylic amine equivalents have been prepared from the corresponding aldehydes, carbamates, and chiral (E)-crotylsilanes in a highly stereoselective manner.
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