Alkyl phosphines promoted reductive coupling of acyl cyanides: formation of O-acyl cyanohydrins

In the presence of alkyl phosphines, reductive coupling of acyl cyanides proceeded smoothly at room temperature in THF to give the corresponding O-acyl cyanohydrins in moderate to high yields. The possible mechanism was discussed on the basis of deuterium labeling and control experiments, indicating that one hydride transfer took place from alkyl phosphine to cyanohydrin.