Silanes, process for their preparation, and their use

A process for protecting hydroxyl, mercapto, carboxyl, amino and amide groups in organic syntheses, which comprises reacting an organic compound carrying hydroxyl, mercapto, carboxyl groups or alkali metal salts thereof, amino and/or amide groups, or an aldehyde or a ketone having an .alpha.-H atom with a compound of the formula Ib ##STR40## in which X is an ester group of an inorganic or organic acid and m is a number from 1 to 4, R.sup.1 and R.sup.2 independently of one another are linear or branched C.sub.1 -C.sub.12 -alkyl, C.sub.5 -cycloalkyl or C.sub.6 -cycloalkyl or unsubstituted or C.sub.1 -C.sub.6 -alkyl-substituted benzyl, or R.sup.1 and R.sup.2 together are tetramethylene or pentamethylene and R.sup.3 to R.sup.6 independently of one another are linear or branched C.sub.1 -C.sub.12 -alkyl, unsubstituted or C.sub.1 -C.sub.6 -alkyl-substituted phenyl or phenyl-C.sub.n H.sub.2n - with n=1 to 6, C.sub.5 -cycloalkyl or C.sub.6 -cycloalkyl, R.sup.3 and R.sup.5 together and/or R.sup.4 and R.sup.6 together are tetramethylene or pentamethylene or R.sup.3 and R.sup.4 together and/or R.sup.5 and R.sup.6 together are trimethylene or tetramethylene, to form a removable protective group on said organic compound, and eliminating the protective group after the organic synthesis reaction has been carried out.