gem-Difluoroolefination of Amides

A metal-free one-pot process for the gem-difluoroolefination of amides is described. The reaction is based on interaction of generated in situ α-chloroiminium salts with difluorinated phosphorus ylide formed from difluorocarbene and triphenylphosphine. The olefination involves nucleophile-assisted dephosphorylation and proceeds within one hour at low temperature. The gem-difluoroenamines were used in further transformations leading to a variety of fluoroalkylated amines.

Synthesis of Difluoroalkylated Heteroarenes via Difluorocarbene

A diversity-oriented and C2-selective synthesis of difluoroalkyl-substituted heteroarenes from three fragments, N-methoxyazinium salts, difluorocarbene, and electrophilic or radical reagents, is described. The reaction proceeds via the addition of difluorinated phosphorus ylide to in situ methylated heteroarene N-oxides, leading to phosphonium salts, which can undergo further transformations under basic or photoinduced conditions.