Electrophilic 1,3-C -> N- and -N -> C- migrations in saturated systems

A new type of intramolecular electrophilic rearrangements involving the shi ft of COOAlk groups from carbon to an N-anionic center is considered. Carba nionic species with COOAlk groups at anionic centers containing no acidic h ydrogen react unusually with alkyl(aryl) iso(thio)cyanates giving carbamate s as a result of insertion of RNCX into the C-C bond. The kinetics and mech anism of insertion of aryl isocyanates into the C-C bond of the phosphonium zwitterion obtained from triisopropylphosphine and ethyl 2-cyanoacrylate a re discussed. The reaction of cc-carbanions derived from N,N-disubstituted amides with methyl trifluoromethanesulfonate result in O-methylation. Some possibilities of back N-->C- migrations are considered.