Metal Free Synthesis of α-Acetoxy/Hydroxymethyl Ketones from Propargylic acetates

摘要

An acid,HI promoted di-deiodination process for the synthesis of α-acetoxy/hydroxymethyl ketones from α’-acetoxy-α,α-dihaloketones has been reported.The process is very general in terms of structural diversity of both tertiary-as well as secondary-acetoxy possessing diiodoketones and found to be very efficient.The proposed mechanism involves as initial carbonyl activation by proton(acid)followed by the deiodination by Lewis base(iodide or water),for both the deiodination reactions.By extending this idea of acid activation during deiodination,further we have also developed a cascade conversion of propargylic acetates to corresponding α-acetoxy/hydroxymethyl ketones under metal free conditions.This strategy is unique and high yielding for total four functional group transformations,i.e.,propargylic acetate to diiodoketone to mono-idodoketone to acetoxymethyl ketone to hydroxymethyl ketone.