Highly Regioselective Fluorination and Iodination of Alkynyl Enolates

摘要

A simple yet efficient approach to various functionalized quaternary alpha-alkynyl alpha-fluoro esters and gamma-iodoallenoates from readily available allenoates through an alkynyl enolate intermediate generated by LDA is presented. Reaction of this alkynyl enolate with NFSI gives the alpha-product (alpha-alkynyl-alpha-fluoro ester), whereas the reaction of the silyl ether of alkynyl enolate with I-2 gives solely the gamma-product (iodoallenoate).