Photochemical synthesis of oxiranes using DABSO-activated sulfinates and allylic peroxides

The family of oxiranes encompasses a variety of compounds with extensive applications across different fields. Herein, we report the development of a visible-light irradiation method using sulfinates in the presence of DABSO to form sulfonyl radicals, which results in the efficient sulfone-epoxidation of allylic peroxides, directly accessing a considerable range of highly functionalized strained oxiranes. The key to this photoinduced epoxidation process lies in the reactivity of the in-situ generated ammonium sulfinate complex with DABSO, which readily produces a sulfonyl radical that reacts with alkenes, as supported by mechanistic studies. Moreover, the utility of the approach, enhanced by an easy to apply protocol for the open-ring reaction of resulting oxirane motifs, is highlighted to the synthesis of numerous synthetically useful building blocks at previously difficult to access positions within organic molecules and bioactive compounds, thereby facilitating the achievement of synthetic targets. The family of oxiranes encompasses a variety of compounds with extensive applications across different fields. Herein, the authors report the photochemical syntheses of a range of highly functionalized strained oxiranes.