Decomposition of 1-adamantyl chloroglyoxylate (I) in nitrobenzene at 105° is about 40,000 times slower than the analogous decomposition of 1-adamantyl chloroformate (II). In benzene at 105°, the ester (I) forms appreciable amounts of 1-phenyladamantane. Unlike the heterolytic reactions of ester (II), decomposition reactions of ester (I) may well be homolytic in nature. In contrast to the fragmentation observed during solvolysis–decomposition of ester (II), ester (I) undergoes a rapid methanolysis to give the mixed oxalate ester. However, ester (II) will give mixed carbonate esters in the presence of alkoxide or upon extensive dilution of the alcohol with benzene.