Fig. 8: Optimization for the reaction conditions of the 2nd step.

Reaction conditions: 1) 1a (0.3 mmol), cyclohexane (10 equiv.), FeCl3 (0.001 equiv.), FeCl2•4H2O (0.5 equiv.), L6 (0.5 equiv.), and CH3CN (3 mL) under N2 and irradiation of a 30 W 365 nm LED for 48 h. 2) Catalyst (1 mol%) and solvent (3 mL) under N2 and irradiation of a 30 W LED for 3 h (C1 with 365 nm, 405 nm, 455 nm for 0.5 h, 5 h, and 12 h, respectively). The total yields were the isolated yields after two successive steps. Yields of 3a + 4a or 5a + 6a were determined by 1H NMR. The E-selectivity was detected by 1H NMR or GC-MS.