2, 5-Dimethyl-2, 4-hexadiene (1) was studied as a singlet oxygen acceptor in various solvents. 1 undergoes concomitantly the three well-known modes of singlet oxygen reactions:(1) the ene-reaction to give the allylic hydroperoxide 3,(2) the (4+ 2)-cycloaddition to give the endoperoxide 4, and (3) the (2+ 2)-cycloaddition to give the dioxetane 2. Beyond that (and in contrast to simple olefins), there are (4)“physical” quenching and (5) a “vinylog ...
