Thermal rearrangement of benzisoxazole- and naphthisoxazolequinones in solution and in the solid state. Stereoselective synthesis of γ-cyanomethylidenebutenolides.
作者:M.Victoria Martínez-Díaz、Salomé Rodríguez-Morgade、Wolfram Schäfer、Tomás Torres
DOI:10.1016/s0040-4020(01)80370-7
日期:1993.3
accessible benzisoxazolequinones 1 undergo thermal induced highly stereoselective rearrangement in solution to afford quantitatively γ-cyanomethylidenebutenolides 3. The transformation can be explained by the formation of a vinylogous nitrene intermediate 4, which undergoes an intramolecular acid-catalysed rearrangement. Compounds 3 react easily with alcohols in Michael addition. On the other hand,
易获得的苯并异恶唑醌1在溶液中经历热诱导的高度立体选择性重排,从而定量提供γ-氰基亚甲基丁烯化物3。该转化可以通过形成乙烯基亚硝基中间体4来解释,该乙烯基中间体经历分子内酸催化的重排。在迈克尔加成反应中,化合物3容易与醇反应。另一方面,苯并异恶唑醌1和萘并恶唑醌2在固态下进行分子间热重排,从而在这种情况下分别给出相应的N-甲基异恶唑酮醌20和11作为主要产物。