Transition-Metal-Free Allylic Defluorination Cross-Electrophile Coupling
Employing Rongalite
Abstract
The conversion of CF3-alkenes to gem-difluoroalkenes using reductive
cross-coupling strategy has received much attention in recent years,
however, the use of green and readily available reducing salt to mediate
these reactions remains to be explored. In this work a concise
construction of gem-difluoroalkenes, which requires neither a catalyst
nor a metal reducing agent, was established. Rongalite, a safe and
inexpensive industrial product, was employed as both a radical initiator
and reductant. This procedure was compatible with both linear and cyclic
diaryliodonium salts, enabling a wide variety of substrates
(>70 examples). The utility of this approach was
demonstrated through gram-scale synthesis and efficient late-stage
functionalizations of anti-inflammatory drugs.