Immonium ylides derived from halocarbenes in the synthesis of nitrogen-containing compounds

Reactions of halocarbenes with imines, ketenimines, and aromatic azaheterocycles, which proceed through the corresponding azomethine ylides, keteneimine ylides, and cycloimmonium ylides, are reviewed. New routes for the synthesis of halo- and nitrogencontaining compounds using the transformations of halosubstituted immonium ylides are discussed.The paper is based on an invited lecture at the fifth Conference on Carbene Chemistry (Moscow, September 16–18, 1992).Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 4, pp. 646–654, April, 1993.