Stereoselective domino assembling of five molecules: one-pot approach to $(2^\primeR^*,3S^*,4^\primeR^*)$-$2^\prime,4^\prime$-diaryl-$1^\prime,4^\prime$-dihydro-$2^\primeH $-spiro[indoline-$3,3^\prime$-pyridines]

Abstract

A new stereoselective multicomponent reaction has been found: domino assembling of two equivalents of benzaldehyde, malononitrile, oxindole and excess of ammonium acetate in acetonitrile resulted in the formation of previously unknown $(2^\primeR^*,3S^*,4^\primeR^*)$-$6^\prime$-amino-2-oxo-$2^\prime,4^\prime$-diaryl-$1^\prime,4^\prime$-dihydro-$2^\primeH$-spiro[indoline-$3,3^\prime$-pyridine]-$5^\prime$-carbonitriles. Optimized reaction conditions and a mechanistic rationale for this multicomponent transformation are presented. This complex one-pot process occurs under mild conditions. The final compounds need no labor-intensive purification.

Keywords

• Malononitrile
• Oxindole
• Domino reaction
• Spiro[indoline-3
• 3$^\prime$-pyridine]
• Knoevenagel condensation
• Michael addition