HETEROGENEOUS PERMANGANATE OXIDATIONS .7. THE OXIDATION OF ALIPHATIC SIDE-CHAINS

Alkylbenzene side chains are oxidized at the benzylic position when tr eated under heterogeneous conditions with permanganate adsorbed on a s olid support. The products are alcohols if the benzylic carbon is tert iary, or ketones if it is secondary. Carbon-carbon bond cleavage, whic h usually occurs when these same compounds are oxidized by permanganat e under homogeneous conditions, does not occur. A unique selectivity i s observed for the oxidation of derivatives of indane, 1, and tetralin , 2, in which one of the methylenes is replaced by an oxygen. If the o xygen is in the alpha-position, no reaction occurs; if it is in the be ta-position; good yields of the corresponding lactone are obtained. A mechanism consistent with the observed selectivity has been proposed.