The Vicinal Orientation. I. The Pivaloylation of Polymethylbenzenes

The direct introduction of a pivaloyl group by Friedel-Crafts acylation has been carried out with the following polymethylbenzenes: o-xylene, m-xylene, hemimellitene, pseudocumene, mesitylene, prehnitene and durene. The decarbonylation was not very significant, and seven new polymethylpivalophenones were prepared in fairly high yields. The hydrocarbon mixtures obtained simultaneously in these reactions usually consisted of at least four or five substances. In the pivaloylation of durene, the Jacobsen-type migration (vicinal orientation) of a methyl group was observed.