Mechanochemical‐ (Hand‐Grinding‐) Assisted Domino Synthesis of Fused Pyran‐Spirooxindoles under Solvent‐ and Catalyst‐Free Condition.

An efficient and green strategy is developed to synthesize 2‐amino‐2‐oxospiro [indoline‐3, 4′‐pyran]‐3′‐carbonitriles. The method encompasses a domino multicomponent reaction using isatin or acetanaphthelenequinone, malononitrile or ethylcyanoacetate and enolizable 1, 3‐dicarbonyl compounds without any promoter and catalyst in one pot through hand grinding in excellent yields within minutes. Fused pyran‐spiro‐oxindoles have been synthesized from readily available starting materials such as isatin, malononitrile and some 1, 3‐dicarbonyl compounds by employing domino multicomponent reaction strategy assisted by mechano‐chemical (hand grinding) technique under solvent and catalyst free conditions. [ABSTRACT FROM AUTHOR]