Abstract
Free-radical hydrophosphonylation of alkenes by H-phosphonates has been reported by other groups to occur under harsh conditions. On the other hand, we demonstrate in this paper that the hydrophosphonylation of alkene functionalized carbohydrates (enopyranoses) by dimethyl H-phosphonate can be carried out with high efficiency under neutral conditions at room temperature and with short reaction times using UV/Vis light irradiation in the presence of a suitable photoinitiator. Indeed, a range of structurally different allyl C-glycosides and exo-glycals were transformed into the corresponding glycosylalkyl phosphonates that were isolated in excellent yields (88–98 %), except for one case (45 %). A mechanism similar to that of the free-radical photoinduced hydrothiolation of alkenes is proposed.