Construction of 4‑Vinyl-1,2-oxaphospholane 2‑Oxides from Vinyloxiranes and Phosphoryl Diazomethanes

Various 4-vinyl-1,2-oxaphospholane 2-oxides are prepared in good to excellent yields from vinyloxiranes and in situ-generated phosphenes from phosphoryl diazomethanes via the phosphene-induced ring expansion of oxiranes. The reaction is a novel and expeditious strategy for the synthesis of 1,2-oxaphospholane 2-oxide derivatives, featuring ring expansion of readily available starting materials, high atom economy, no catalyst, a fast reaction rate, broad functional group tolerance, high yields, and separable diastereomers.