Synthesis of Trisubstituted Furans via Copper(I)-Catalyzed Strain-Driving Cycloisomerization/Annulative Fragmentation

Org Lett. 2022 Mar 25;24(11):2220-2225. doi: 10.1021/acs.orglett.2c00578. Epub 2022 Mar 14.

Abstract

The in situ formed furan-fused cyclobutenes via Cu(I)-catalyzed cycloisomerization of readily available allenyl ketones bearing a cyclopropyl moiety are a highly reactive and powerful species, which undergo annulative fragmentation with terminal ynones to afford a wide variety of functional furans in moderate to high yields. This ring-distortion protocol features an unprecedented strain-controlled cycloisomerization/Diels-Alder/retro-Diels-Alder (CDRD) sequence under mild conditions.