Photoredox Catalytic Phosphite‐Mediated Deoxygenation of α‐Diketones Enables Wolff Rearrangement and Staudinger Synthesis of β‐Lactams.

A novel visible‐light‐driven catalytic activation of C=O bonds by exploiting the photoredox chemistry of 1,3,2‐dioxaphospholes, readily accessible from α‐diketones and trialkyl phosphites, is reported. This mild and environmentally friendly strategy provides an unprecedented and efficient access to the Wolff rearrangement reaction which traditionally entails α‐diazoketones as precursors. The resulting ketenes could be precisely trapped by alcohols/thiols to give α‐aryl (thio)acetates and by imines to afford the valuable β‐lactams in up to 99 % yields. [ABSTRACT FROM AUTHOR]