Cobalt-catalyzed enantioselective intramolecular reductive cyclization via electrochemistry

1,6 enynes are a useful synthetic building block, but their use asymmetric intramolecular reductive couplings with cobalt catalysts have not been well-explored. Here, the authors describe an enantioselective intramolecular reductive coupling of enynes via the combination of electrochemistry and cobalt catalysis. Transition-metal catalyzed asymmetric cyclization of 1,6-enynes has emerged as a powerful method for the construction of carbocycles and heterocycles. However, very rare examples worked under electrochemical conditions. We report herein a Co-catalyzed enantioselective intramolecular reductive coupling of enynes via electrochemistry using H2O as hydride source. The products were obtained in good yields with high regio- and enantioselectivities. It represents the rare progress on the cobalt-catalyzed enantioselective transformation via electrochemistry with a general substrate scope. DFT studies explored the possible reaction pathways and revealed that the oxidative cyclization of enynes by LCo(I) is more favorable than oxidative addition of H2O or other pathways.