Fluorinated Sulfinates as Source of Alkyl Radicals in the Photo-Enantiocontrolled β-Functionalization of Enals
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Updated: Oct 8, 2025

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Ricardo I Rodríguez1, Marina Sicignano1, José Alemán1,2
1Organic Chemistry Department, Módulo 1, Universidad Autónoma de Madrid, 28049, Madrid, Spain.
Abstract:
The generation of sulfonyl radicals has long been known as a flexible strategy in a wide range of different sulfonylative transformations. Meanwhile their use in alkylation processes has been somehow limited due to their inherent difficulty in evolving to less-stable radicals after sulfur dioxide extrusion. Herein we report a convenient strategy that involves gem-difluorinated sulfinates as an "upgrading-mask", allowing these precursors to decompose into their corresponding alkyl radicals. The electron-donor character of sulfinates in the formation of an electron donor-acceptor (EDA) complex with transient iminium ions is displayed, achieving the first example of a stereocontrolled light-driven insertion of gem-difluoro derivatives into unsaturated aldehydes. This methodology is compatible with flow conditions, maintaining identical levels of enantiocontrol.
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