Versatile C─H Alkylation and Alkylidenation via Catalytic Alkylidene Transfer of Enones

Abstract

The alkylidene transfer reactions of alkenes are of particular significance but challenging. Here, we report that enones can serve as diverse alkylidene sources for catalyst-controlled selective C─H alkylation and/or alkylidenation of various nucleophiles. Treatment of a mixture of ketone (or lactam), enone, and diarylmethanol, with a catalytic amount of Y[N(TMS)₂]₃, gave the corresponding α-C─H bond alkylation products derived from the alkylidene transfer from enones to ketones/lactams, whereas the reaction of enones with various C-nucleophiles in the presence of KOH as a catalyst resulted in C─H alkylidenation. Moreover, the application of these strategies for the late-stage modification or structural simplification of some bioactive molecules is also presented. These alkylidene transfer reactions are characterized by operational simplicity, mild reaction conditions, and remarkable catalyst-controlled product outcomes. These results not only demonstrate a significant potential for easily accessible and recyclable enones to serve as versatile alkylidene sources in C─H alkylation and alkylidenation but also provide an attractive and concise method for hydrodealkylidenation of electron-deficient alkenes.