A Facile Synthesis of Vinyl and Allylic 2,2,2-Trifluoroethyl Phosphonates

Condensation of several representative aldehydes with the anion derived from tetrakis(2,2,2-trifluoroethyl) methylenediphosphonate, a new Wadsworth-Emmons reagent, afforded (Z)-vinyl phosphonates in good yields. The latter, when treated with a catalytic amount of potassium tert-butoxide in DMSO isomerized to the corresponding (E)-allylic phosphonates, which produce E,Z-dienes when reacted with a second aldehyde.