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

An efficient one-pot method for the preparation of α-iodo-substituted α,β-unsaturated aldehydes (α-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 α-iodoenal derivative in good overall yield by oxidation with molecular O2.