ZnI2-Catalyzed Cyanation of Acyl Chlorides with TMS-CN: An Interesting Role of Iodine

Both aliphatic and aromatic acyl cyanides have been synthesized with TMSCN and acyl chloride with ZnI2 (0.5 mol%). However the in situ generated I2 is proposed accounting for the formation of by-product O-TMS enolate at high catalyst loading rather than 0.5 mol%. Asymmetric reduction of benzoyl cyanide with borane has been explored in 82% yield and 24% ee. Keywords: Acyl cyanide, catalysis, cyanation, iodine, Lewis acids, nitrile, cyanohydrin, asymmetric reduction