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Updated: Jan 13, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Base-Promoted [3 + 2] and [2 + 1] Annulation of Alkenyl Sulfonium Salts to Access 2-Oxazolines and Cyclopropanes
Sha Peng1, Ding Luo1, Li-Mei Duan1
1College of Chemistry and Bioengineering, Hunan University of Science and Engineering, 425100 Yongzhou, China.
Abstract:
A base-promoted annulation reaction of alkenyl sulfonium salts with amides and acetophenones has been readily developed. This method enables the regioselective synthesis of various 2-oxazoline and cyclopropane compounds in good to high yields with a wide substrate scope and high functional group tolerance. Notably, this practical [3 + 2] or [2 + 1] annulation strategy circumvents the need for transition-metal catalysts, strong oxidants, and harsh reaction conditions, thereby enhancing its appeal in organic synthesis.
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