The nucleophilicity of M(SPh) 3 (M = P,As) and L-As(SPh) 2 (L = Ph,2-O 2 N-Ph) towards fatty acyl chlorides,RCOCl

Abstract

The reaction of P(SPh)₃, As(SPh)₃, Ph-As(SPh)₂ and 2-O₂N-C₆H₄-As(SPh)₂ with palmitoyl chloride was studied. In dichloromethane at room temperature these reactions did not give the thiol ester RCOSPh, but diphenyl disulfide PhSSPh instead, with yields that were depended on the absence or the presence of an activator [pyridine or 4-dimethylaminopyridine (DMAP)]. At 90°C P(SPh)₃ and palmitoyl chloride gave RCOSPh but not PhSSPh either in the absence or in the presence of pyridine or DMAP. On the other hand, As(SPh)₃, Ph-As(SPh)₂ and 2-O₂N-C₆H₄-As(SPh)₂ with palmitoyl chloride at 90°C gave mixtures of RCOSPh and PhSSPh in proportions depending on the absence or the presence of pyridine or DMAP. Probable mechanistic paths to these products are proposed.