Theoretical study of geometrical effect on the deoxygenation of epoxide by singlet carbenes

The mechanism of the abstraction of oxygen from epoxide by carbenes has been investigated using the B3LYP/6-31G∗ and MP2/6-311++G(d,p)//B3LYP/6-31G∗ levels of theory. According to our model calculations, the reactivity of carbene decreases in the order: four-membered ring carbene > six-membered ring carbene > three-membered ring carbene > five-membered ring carbene ≫ vinylidene. Moreover, the present work shows that the singlet–triplet splitting of a carbene can be used as a guide for the prediction of its reactivity.