We systematically surveyed the reaction conditions by varying the copper salts, the ligands, the solvents, the light sources, and the temperatures (see Supporting Information, section 3.2). The optimal conditions were established to be irradiating (purple LEDs) a THF/toluene solution of 4-phenyl-1,3-enyne 6a, oxime carbonate 2a, and phenylboronic acid 3a in the presence of Cu(CH3CN)4OTf