A View of Unusual Peroxides

摘要

Chemical processes involving oxygen can lead to unstable peroxide molecules such as three-membered ring dioxiranes (see the first figure). Indirect evidence points to the existence of many dioxiranes, but few have been characterized structurally. On page 259 of this issue, Ho et al. (1) report the structure of a novel peroxide, phosphadioxirane 1, which contains a phosphorus atom in the dioxirane ring. Until the 1970s, it was commonly believed that cyclic dioxirane structures, such as dimethyldioxirane 2, could not exist. Today, reactions of dioxiranes with organic substrates are well established. The organic group CR_2 (where R may be any hydrocarbon substituent, such as methyl) can also be replaced by other chemical groups to yield XO_2, where X may for example be R_3P, RN, R_2Si, R_2S, or R_2Se. The stability of these het-eroatom-containing dioxiranes varies widely, allowing new kinds of peroxide structure and reactivity to be explored.