Stereoselective Synthesis of β‑Glycosyl Esters via TBHP-Mediated Oxidative Coupling of Aldehydes and Cyclic Enol Ethers

A TBHP-mediated, metal-free strategy
has been developed for the
direct one-step synthesis of glycosyl esters from readily available
glycals and aldehydes. This protocol proceeds under mild conditions
and enables the highly stereoselective formation of β-glycosyl
esters in excellent yields. It features a broad substrate scope, good
functional group tolerance, and compatibility with structurally complex
molecules. Furthermore, the method delivers high yields even on a
gram scale, underscoring its practical utility in synthetic applications.
Mechanistic investigations and control experiments indicate that the
reaction proceeds through a free radical pathway involving the initial
generation of peracids. These peracids react with glycals to produce
a glycal epoxide intermediate, which subsequently undergoes nucleophilic
attack by the acids released from peracids, affording the desired
β-glycosyl esters.