Fig. 3: Substrate scope.

Reaction conditions: enone (0.2 mmol), 10 mol% Mg(ClO4)2, and a diene (0.6 mmol) in MeCN (2 mL) in the presence of 395 nm LEDs at room temperature under argon, a single isomer was detected unless noted otherwise. a Diene 2 was used. b 370 nm LEDs were used. c 10 mol% Cu(NTf2)2 was used instead. d Enone 1 was used. Cu(NTf2)2 Copper(II) bis(trifluoromethanesulfonyl)imide.