Decarboxylative 1,4-carbocyanation of 1,3-enynes to access tetra-substituted allenes via copper/photoredox dual catalysis

We disclose herein the first example of merging photoredox catalysis and copper catalysis for radical 1,4-carbocyanations of 1,3-enynes. Alkyl N-hydroxyphthalimide esters are utilized as radical precursors, and the reported mild and redox-neutral protocol has broad substrate scope and remarkable functional group tolerance. This strategy allows for the synthesis of diverse multi-substituted allenes with high chemo- and regio-selectivities, also permitting late stage allenylation of natural products and drug molecules.

Automated summary

In this study, we combine photoredox catalysis and copper catalysis for the first time to achieve radical 1,4-carbocyanations of 1,3-enynes. By utilizing alkyl N-hydroxyphthalimide esters as radical precursors, the mild and redox-neutral protocol shows broad substrate scope and remarkable functional group tolerance. This strategy enables the synthesis of diverse multi-substituted allenes with high chemo- and regio-selectivities, allowing late stage allenylation of natural products and drug molecules.