Synthesis of polysubstituted aromatic compounds and aromatisation process for use therein

摘要

In a retro-Diels-Alder reaction the starting cycloadduct is protected by -OH or -OP groups to form a desired benzene derivative or heteroaromatic compound, with the concomitant elimination of a dioxolene species. The protecting groups P are preferably comprised in a cyclic thiocarbonate or cis-isopropyldienedioxy group. The cycloadduct may be prepared by Diels-Alder cycloaddition of an acetylenic dienophile to a cyclohexadiene-cis-diol, and the cyclohexadiene may be formed by biological oxidation of an arene. The process allows desired aromatised products to be produced in uniformly high yields and the reaction is generally initiated at lower temperatures than known methods of synthesis which evolve ethylene. The by-products are usually non-volatile and may spontaneously polymerise.