Regioselective Mitsunobu Reaction of Partially Protected Uridine

Mitsunobu reaction of partially acylated uridine proceeds with high regioselectivity for intramolecular SN2 anhydro linkage closuring. Under the reaction conditions, an isomeric mixture of diacyl uridine derivatives with either free 2′- or 3′-hydroxyl group was transformed into a single cyclonucleosidic product, 2,2′-anhydro-3′,5′-di-O-acyluridine. This paper presents a possible mechanism of the reactions, the explanation of observed phenomenon based on semiempirical and density functional theory (DFT) calculations and possible utility of this synthetic pathway.

部分酰化尿苷的光延（Mitsunobu）反应可高区域选择性地进行分子内SN2型脱水键环合。在该反应条件下，带有游离2'-或3'-羟基的二酰化尿苷衍生物异构体混合物，可转化为单一的环核苷产物2,2'-脱水-3',5'-二-O-酰基尿苷。本文阐述了该反应的可能机理、基于半经验方法与密度泛函理论（DFT）计算的实验现象解释，以及该合成路径的潜在应用价值。