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

Combination of a phosphinidene precursor, B(C 6 F 5 ) 3 and 4-ethynyltoluene afforded the FLP addition product, Et 2 N(C 14 H 10 )PC(Tol)CH (B(C 6 F 5 ) 3 ) 2. Compound 2 reacted with halides, pseudo-halides or Me 3 SiSPh to provide a facile route to the salts of anionic phosphines while reaction with PEt 3 gave the zwitterion Et 3 PCHC(SiMe 3 )P(NEt 2 )C(Tol)CHB(C 6 F 5 ) 3 8. This latter species reacted with an alkyne to give a phosphine donor with both olefin-linked cationic and anionic substituents.