The carbonylation of C6–C10n-alkanes with CO in the presence of CBr4· 2AlBr3 at–40° C and 1 atm CO leads to the products of non-destructive carbonylation, ie, the esters of tertiary carboxylic acids, R1C (Me) 2COOR and R2 (Et) C (Me) COOR, after the workup of reaction mixtures with ROH.