Photoinduced Temperature-Regulated Selective Carbene C-H Insertion for the Synthesis of Functionalized Spiro-β-lactones and -lactams.

A temperature-regulated catalyst-free photoinduced selective carbene C-H insertion strategy was realized to efficiently synthesize spiro--lactones and -lactams, which hold considerable promise in drug discovery programs. The reaction shows broad applicability across a range of α-diazo esters and amides with various ring sizes and substituents and has been demonstrated to successfully achieve the late-stage spirocyclization of natural/bioactive compounds. The obtained products could be transformed into spiro-oxetanes, -azetidines, and -cyclopropanes, privileged scaffolds with broad utility in medicinal chemistry.