The invention relates to new alkoxyamines suitable for hydrosilylation reactions, to siloxane modified alkoxamines and to siloxane modified polymers as well as to their use. The alkoxamines are compounds of formula (I) or (II) wherein A is a group capable of forming a stable free nitroxyl radical A. which is bound via its oxygen atom to the carbon atom; R.sub.1 and R.sub.2 independently of one another are hydrogen, C.sub.1-C.sub.18-alkyl, C.sub.3-C.sub.8cycloalkyl or phenyl which are unsubstituted or substituted by NO.sub.2, halogen, amino, hydroxy, cyano, carboxy, C.sub.1-C.sub.4alkoxy, C.sub.1-C.sub.4alkylthio, C.sub.1-C.sub.4alkylamino or di(C.sub.1-C.sub.4alkyl)amino; R.sub.3, R.sub.4 and R.sub.5 independently of one another are hydrogen or C.sub.1-C.sub.18alkyl or phenyl; or R.sub.3 and R.sub.5 together with the linking group C.dbd.C form a 5 to 12 membered ring; R.sub.6 is X hydrogen or C.sub.1-C.sub.l8alkyl or phenyl; X is O, NH or NR.sub.7, wherein R.sub.7 is C.sub.1-C.sub.18alkyl, C.sub.3-C.sub.8cycloalkyl or phenyl; Y is a direct bond, C.sub.1-C.sub.30alkylene or C.sub.6-C.sub.12arylene.