Synthesis and Structure of 1-Aza- and I-Phospha-2-titanacyclobut-4-enes

摘要

Oxatitanacyclobutanes and azatitanacyclobutenes are discussed as intermediates in reactions of carbenoid titanium compounds with carbonyl compounds or nitriles, respectively. The high electrophilicity of the metal center has to date prohibited the isolation and characterization of 1 and 3; spontaneous ring opening affords either car bony! olefination (1 ->2), or products of intermediately formed vinylimido species 4 corresponding to the reaction of 3 -> 4.