[2-[2-(1-adamantyl)butan-2-yloxy]-2-oxoethyl] 2,2-dimethylbutanoate;[2-[3-(1-adamantyl)pentan-3-yloxy]-2-oxoethyl] 2,2-dimethylbutanoate;2-O-[2-[2-(1-adamantyl)propan-2-yloxy]-2-oxoethyl] 1-O-[2-(2,2-dimethylbutanoyloxy)ethyl] cyclohexane-1,2-dicarboxylate;[2-(1,1-dicyclohexylethoxy)-2-oxoethyl] 2,2-dimethylbutanoate;[2-(1,1-dicyclohexylpropoxy)-2-oxoethyl] 2,2-dimethylbutanoate;[4-[(2-methyl-2-adamantyl)oxy]-4-oxobutyl] 2,2-dimethylbutanoate