Sulfinate Allenyl Carbenoids: Synthesis of 2,5-Dihydrofurans by Domino Rearrangement and Cyclization

摘要

Propargylic sulfinates can be successfully deprotonated at the acetylenic carbon with lithium hexamethyldisilazide. The resulting anions add successfully to aldehydes and ketones. Treatment of these adducts with a silver cation results in both a 2,3-sigmatropic shift and a cyclization of the resulting allene to afford 2,5-dihydrofurans in excellent yields.