Syntheses of alpha-fluoro-alpha,beta-unsaturated thioamides and thiazolines from a fluorophosphonodithioacetate.

A high-yielding synthesis of methyl fluoro(diethoxyphosphono)dithioacetate starting from its difluorinated analogue is reported. Fluorophosphonothioacetamides and -methylthiazolines, prepared from this new dithioester, have been successfully transformed into highly functionalized fluoroalkenes. Good stereoselectivity in favor of the E isomer was observed from the fluorophosphonomethylthiazolines. The potential of these new fluorinated olefinating reagents for the synthesis of modified peptides and glycosides is also disclosed.