Iodo Meyer–Schuster Rearrangement of 3‑Alkoxy-2-yn-1-ols for β‑Mono (Exclusively Z‑Selective)-/Disubstituted α‑Iodo-α,β-Unsaturated Esters

We herein present the iodo Meyer–Schuster rearrangement of 3-alkoxypropargyl alcohols for α-iodo-α,β-unsaturated esters using iodine or NIS in dichloromethane at ambient temperature. Substrates prepared from both aldehydes and ketones are found to be equally good feedstock for the reaction to produce β-mono- and -disubstituted products. Irrespective of the substitution, substrates prepared from aldehydes gave Z-isomers exclusively.