Pyridine as a Borane Scavenger to Avoid Overreduction During the Conversion of Acid Chlorides to the Corresponding Aldehydes Using Sodium Borohydride

By use of sodium borohydride in N, N-dimethylformamide solution containing a molar excess of pyridine as a borane scavenger, direct conversion of both aliphatic and aromatic acid chlorides to the corresponding aldehydes can be achieved in >70% yield with minimal (5–10%) alcohol formation.