α-Bromination of aldoximes. A route to fused azetidines.

Abstract Unlike aldehydes and aldoximes, O-silylated aldoximes 2 are smoothly α-brominated with NBS to produce 3 , useful intermediates in the conversion to vinylnitroso species or in α-substitution reactions. For instance, 3 + 9 → 10 provided precursors for nitrile oxide-olefin cycloadditions.