Polyamine macrocycles having organosilicon moieties were synthesized through new addition reaction of lithium alkylamide toward vinylsilane derivatives. 6-Ethyl-3,3-dimethyl-3-sila-6,9-diazaundecane in the presence of lithium alkylamide took place polyaddition reactions, consisting of diamine and organosilicon units alternatively. By increasing possibilities of intramolecular nucleophilic attack, the