A facile synthesis of alkylidenebutenolides via thermal rearrangement of benzisoxazolequinones
摘要:
Benzisoxazolequinones 1 readily accesible from 2-carboxy-1,4-hydroquinone undergo thermic induced highly stereoselective rearrangement in solution to produce quantitatively gamma-cyanomethylidenebutenolides 2.
Thermal rearrangement of benzisoxazole- and naphthisoxazolequinones in solution and in the solid state. Stereoselective synthesis of γ-cyanomethylidenebutenolides.
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-catalysedrearrangement. Compounds 3 react easily with alcohols in Michael addition. On the other hand,