Fig. 5: Mechanistic studies.

a Radical trapping experiment in the presence of 2,2,6,6-Tetramethylpiperidinooxy (TEMPO). b DFT calculations for the E/Z-selectivity of 1-phenyl-1,3-butadiene. c DFT calculations for the E/Z-selectivity of 1-cyclohexyl-1,3-butadiene. d DFT calculations for the regioselectivity of [4 + 2] vs [2 + 2]. Transition states are illustrated using CYLview2069.