The present invention relates to the preparation of .OMEGA.-(dimethylisopropenylbenzylurethane) polyalkylene glycols with .alpha.-alkoxy or .alpha.-dihydroxy groups and to the use thereof as hydrolysis-stable macromonomers for the dispersion and crosslinking of polymers ##STR00001## in which A is C.sub.2-C.sub.4-alkylene m is an integer from 5 to 900, and R is C.sub.1-C.sub.20-alkyl, C.sub.6-C.sub.18-aryl or a radical according to formula 2a, 2b, 2c, 3a, 3b or 3c ##STR00002## which is bonded to the terminal oxygen atom of the alkoxy group (A-O) in formula 1 via the valence denoted by *, and in which A is not exclusively C.sub.3- or C.sub.4-alkylene.