One-pot double annulations to confer diastereoselective spirooxindolepyrrolothiazoles.

A novel four-component reaction in one pot as an atom- and step-economic process was developed to synthesize diastereoselectively spirooxindolepyrrolothiazoles through sequential N,S -acetalation of aldehydes with cysteine and decarboxylative [3 + 2] cycloaddition with olefinic oxindoles. High synthetic efficiency, operational simplification and reaction process economy using EtOH as solvent, and only releasing CO 2 and H 2 O as side products confer this approach favorable in green chemistry metrics analysis.