Reactive FLP-alkyne addition products: a route to anionic and zwitterionic phosphines.

Combination of a phosphinidene precursor, B(CF) and 4-ethynyltoluene afforded the FLP addition product, EtN(CH)PC(Tol)CH (B(CF)) 2. Compound 2 reacted with halides, pseudo-halides or MeSiSPh to provide a facile route to the salts of anionic phosphines while reaction with PEt gave the zwitterion EtPCHC(SiMe)P(NEt)C(Tol)CHB(CF)8. This latter species reacted with an alkyne to give a phosphine donor with both olefin-linked cationic and anionic substituents.