Abstract: A process of preparing compounds containing silicon-carbon bonds by the hydrosilation of a hydridoalkoxysilyl reactant with an olefinic reactant comprises operating the process in the presence of a platinum catalyst and a reaction promoter comprising a weakly nucleophilic amine of the formula NZ1Z2Z3 wherein Z1 is an aryl, alkaryl, or aralkyl group of C6 to C20 carbon atoms, or an organosilyl substituent, SiR3, wherein R is an alkyl of C1 to C20 or an aryl of C6 to C10, Z2 is hydrogen, alkyl of C1 to C20, an aryl, alkaryl, or aralkyl group of C6 to C20 carbon atoms or SiR3, wherein R is as previously defined; Z3 is the same as Z1 or Z2, and, optionally, two Of Z1, Z2 and Z3 taken together with the nitrogen atom form an aromatic heterocyclic ring.