Reactions of an intramolecular frustrated Lewis pair with unsaturated substrates: evidence for a concerted olefin addition reaction

The intramolecular frustrated Lewis pair [(mesityl).sub.2]P-C[H.sub.2]-C[H.sub.2]B[([F.sub.6][F.sub.5]).sub.2] is generated in situ by HB[([C.sub.6][F.sub.5]).sub.2] hydroboration of dimesitylvinylphosphine and it has reacted with 1-pentyne by C-H bond cleavage. The studies have shown that the reaction has taken place in an asynchronous concerted fashion with the B-C bond being formed in slight preference to the P-C bond.