Abstract The synthesis of the (α, α-difluoroalkyl) phosphonate analogue of L-phosphoserine, 5, in a form appropriate for solid phase peptide synthesis, is reported. Two independent routes are described, starting from L-serine or (R)-isopropylideneglycerol. In each case, PCF 2 C bond formation is achieved by triflate displacement with diethyl lithiodifluoromethylphosphonate.
