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

Abstract

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.

Synthesis of 3-(Arylsulfonyl)-3-pyrrolines from Allenyl Sulfonamides by Silver Ion Catalysis

“…In the context of the exploration of metal-catalyzed cyclization of allenes, our group has recently reported the synthesis of 2,5-dihydrofurans from α-hydroxy allenes or hydroxy propargylic sulfinates by silver fluoride catalysis . For example, treatment of 1 or 3 with silver fluoride under the conditions noted afforded the dihydrofurans 2 and 4 in 99% and 81% yields, respectively (Scheme ).…”