Carboxylate protective groups, a process for their preparation, their coupling to a funcitonal group, and their useCarboxylates of polar, hydrophilic alcohols of the formula ##STR1## in which R is an unbranched or branched organic radical which contains, as polar members between aliphatic or araliphatic hydrocarbon bridges, ether oxygens, amine nitrogen groups or a mixture of ether and amine groups which can be incorporated into a cyclic structure, where the total length does not exceed 20 members and where, in the case of polyethylene glycol [(CH.sub.2 --CH.sub.2 --O).sub.n ], n indicates the number of the members and is defined as any integer, andR' is an aliphatic or araliphatic radical which has at least one functional group,are suitable as protective groups since they can be introduced selectively into functional groups of organic compounds and eliminated specifically by lipases.