Nucleophilic additions of [(diethoxyphosphoryl)difluoromethyl]lithium to α,β-unsaturated compounds

The presence of HMPA leads to an increase of 1,4- versus 1,2-additions of [(diethoxyphosphoryl)difluoromethyl]lithium onto α,β-unsaturated ketones and provides products of conjugated addition in moderate to good yields. In the absence of HMPA, benzylidine or alkylidine 1,3-diones, malononitriles or malonates as well as nitroalkenes and other Michael acceptors give products of 1,4-addition in good to high yields.