Direct Nucleophilic Difluoromethylation of Carbonyl Compounds
Zuyong Deng1,2, Jin-Hong Lin1,2, Ji Cai1,2
1Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , 345 Lingling Road, Shanghai 200032, China.
Abstract:
Phosphonium salt ([Ph3P(+)CF2H] Br(-), DFPB) was found to be an efficient nucleophilic difluoromethylation reagent. Although DFPB is known as a phosphonium ylide precursor, its reaction with carbonyl compounds under traditional "Wittig reaction conditions" did not give the expected Wittig difluoroolefinated products, but afforded the nucleophilic difluoromethylation products, α-CF2H alcohols. Mechanistic investigation reveals that the unexpected transformation proceeded via the direct transfer of the CF2H group, which resulted from the high P-O affinity.
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