A novel meso bi­cyclo­[2.2.2]octene-based compound was obtained from an attempted Diels–Alder reaction. It crystallizes from p-xylene as a hemisolvate.

in Wiley Online Library (wileyonlinelibrary.com).In an extension of our prior work with indoles and pyrroles, the Diels-Alder chemistry of substituted 2vinylthiophenes was explored, using N-phenylmaleimide as the dienophile. The dienes were prepared from thiophene in two steps by addition to various ketones, followed by dehydration (40-60% overall yields). Although most dienes were obtained as regioisomeric mixtures, the Diels-Alder-derived products were easily purified by chromatography. The main cycloaddition pathway was endo Diels-Alder addition followed by exo ene addition of a second molecule of dienophile (19-33% yields). Several products were desulfurized with Raney nickel (48-62% yields). Unfortunately, no thiophene-derived products showed the promising biological activity of the previously reported indole analogs.