A Novel Multicomponent Synthesis of Polysubstituted 5-Aminooxazole and Its New Scaffold-Generating Reaction to Pyrrolo[3,4-b]pyridine

A novel three-component synthesis of 5-amino oxazole (1) is reported. Its subsequent reaction with alpha,beta-unsaturated acyl chloride leads to polysubstituted pyrrolopyridine (2). A triple domino process, acylation/IMDA/retro-Michael cycloreversion, was involved in the latter process. The methodology allows the quick preparation, from simple and readily available inputs, of highly functionalized title compounds not easily accessed by other methods.