Convergent approach of double intermediates in flow microreactor: flash irreversible carbocations generation enables direct cross–coupling

Abstract In biosynthesis multiple kinds of reactive intermediates are generated, transported, and reacted across different parts of organisms, enabling highly sophisticated synthetic reactions. Inspired by such ideal reaction conditions, herein we report a convergent synthetic approach using double intermediates, carbocations and carbanions, at once. By reactions of unsaturated precursors, such as enamines, with a superacid in a flow microreactor, carbocations were generated rapidly and irreversibly, and before decomposition, they were transported to react with rapidly and independently generated carbanions, enabling direct C–C bond formation. Taking advantage of the reactivity of these double reactive intermediates, the reaction took place within a few seconds, enabling synthetic reactions which are not applicable in conventional reactions.