Divergent syntheses of spirooxindoles from oxindole-embedded four-membered synthon <i>via</i> cycloaddition reactions

Abstract

The construction of five and six membered heterocycle fused spirooxindoles was achieved <italic>via</italic> the [4 + 1] and formal [4 + 2] cycloadditions between our rationally designed four-membered synthons and pyridinium methylides and α-bromoacetophenones, respectively.