Gold Sulfonium Benzylide Complexes Undergo Efficient Benzylidene Transfer to Alkenes.

The gold sulfonium benzylide complexes [(P1)AuCHPh(SR R )]  {B[3,5-CF C H ] } [P1=P(tBu) o-biphenyl; R , R =-(CH ) - (1 a); R =Et, R =Ph (1 b); R =R =Ph (1 c)] were synthesized by reaction of the gold α-chloro benzyl complex (P1)AuCHClPh with sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate and excess sulfide. Complexes 1 undergo efficient benzylidene transfer to alkenes and DMSO under mild conditions without external activation. Kinetic analysis of the reaction of 1 c with styrene was consistent with the intermediacy of the cationic gold benzylidene complex [(P1)AuCHPh] (I).