1,3-Dipolar Cycloaddition of Diazomethane to 1,1-Difluoroallylphosphonates: Application to Synthesis of Cyclopropane Derivatives Having a Diethoxyphosphoryldifluoromethylene Unit
1,3-Dipolarcycloaddition of diazomethane to (1,1-difluoroallyl)phosphonates was examined to give pyrazolines functionalized by a diethoxyphosphoryldifluoromethylene unit. The pyrazolines were transformed to the cyclopropane derivatives possessing a diethoxyphosphoryldifluoromethylene functionality by photolysis.
A series of new buta-1,3-diene derivatives possessing a
(diethoxyphosphinoyl)difluoromethylene unit at the terminal carbon was
prepared to examine the reactivity for DielsâAlder cycloaddition with
various representative dienophiles.