Gold Sulfonium Benzylide Complexes Undergo Efficient Benzylidene Transfer to Alkenes.

The gold sulfonium benzylide complexes [(P1)AuCHPh(SR1 R2 )]+  {B[3,5-CF3 C6 H3 ]4 }- [P1=P(tBu)2 o-biphenyl; R1 , R2 =-(CH2 )4 - (1 a); R1 =Et, R2 =Ph (1 b); R1 =R2 =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).