Desulfonylcyanamidation of α,β-unsaturated sulfones with N-tosyl N-aryl cyanamides (NCTS): access to N-cyanoenaminones

Abstract

Enaminones are versatile building blocks with widespread applications in the synthesis of biologically active molecules, natural products, and synthetic pharmaceutical agents. Herein, we describe a desulfonylcyanamidation between α,β-unsaturated sulfones and cyanamide anions generated in situ from NCTS using CsF as a base. This method provides facile access to highly desirable chemical products such as N-cyanoenaminones and N-cyanoenaminesters, featuring broad substrate scope, high functional group tolerance, good to excellent yields, and transition-metal-free conditions. Additionally, a gram-scale experiment and Lu's [3 + 2] cycloaddition transformation demonstrate the synthetic utility of this protocol.