Enantioselective Reductive Cyclization of Alkynyl-Tethered Cyclohexadienones Catalyzed by Rhodium Complexes.

Although various types of asymmetric cyclization reactions of 1,6-enynes have been established, simple asymmetric reductive cyclization remains underdeveloped. In this study, the enantioselective reductive cyclization of alkynyl-tethered cyclohexadienones (1,6-enynes) has been developed via a chiral pincer rhodium catalyst, affording cis -hydrobenzofurans and cis -hydroindoles with high enantioselectivities (90-99% ee). Furthermore, several synthetic applications and preliminary inhibitory activity studies against SARS-CoV-2 3CL pro are presented.