A new wrinkle in an old reaction

Just when you thought we knew everything there was to know about the Diels Alder reaction, cometh Nature vol. 532 pp. 484 – 488 ’16 in which triple bonds are used in both the diene and the dienophile. Naturally they are all put in the same molecule so they can’t get away from each other. I can’t draw the structure in this post, but it’s worth a look, particularly since a benzyne intermediate is formed in one, and an even more bizarre (and labile) intermediate (a diradical with the unpaired electrons, each on an atom, separated by two more carbons) is formed in the other. It’s sort of chemical bonsai. Enjoy