Synthesis of Some 1-Azirines from -Bromo Ketoximes via Oxazaphospholines

A useful route from α-bromo ketoximes 1 to azirines is described which involves protection of 1 followed by phosphine substitution and deprotection via oxazaphospholine intermediates. The mild deprotection of the oxime ethers involves intramolecular assistance by a phosphonium group. New azirines, including a ring-deuterated species, have been synthesized.