Synthesis of Bridged Oxabicycles via Cascade Reactions involving O-Acyloxocarbenium Ion Intermediates

Org Lett. 2021 Nov 5;23(21):8312-8316. doi: 10.1021/acs.orglett.1c03061. Epub 2021 Oct 22.

Abstract

Compared to related electrophilic species, O-acyloxocarbenium ions (AOIs) have been much less utilized in organic synthesis due to the lack of an efficient formation method. Here, we present a facile and simple approach for the generation of AOI from ester and acetal groups. Based on our AOI system with a pendant nucleophile, we obtained a unique bridged bicyclic system via an epoxonium-like transition state. The proposed mechanism is based on experimental and computational studies.