One-Pot Synthesis of α-Iodo-Substituted α,β-Unsaturated Aldehydes from Propargylic Alcohols

An efficient one-pot method for the preparation of alpha-iodo-substituted alpha,beta-unsaturated aldehydes (alpha-iodoenals) from propargylic alcohol is developed. The reaction proceeds via an iodoallene intermediate, which is generated in situ by the reaction of propargylic alcohol with aqueous HI. The iodoallene intermediate is further transformed to an alpha-iodoenal derivative in good overall yield by oxidation with molecular O(2).