Regioselective synthesis of polyfunctionalized alkyltrisilanes and -tetrasilanes via reductive cross-coupling reaction of aminoalkylsilyl chlorides with lithium

Highly selective cross-coupling reactions promoted by lithium metal have been achieved between aminodichloromonosilanes R(Et(2)N)SiCl2 (R = Me, Et, Ph, Et(2)N) and 2 equiv of Me(3)-SiCl (1) or (Et(2)N)Me(2)SiCl (2) and between aminochlorodisilanes (Et(2)N)(n)Me(3-n)SiSiMe(NEt(2))Cl (n = 1, 2) and I equiv of 1, 2, or (Me(2)N)(n)R(3-n)SiCl (n = 1, R = Et; n = 2, R = Me, Et) in THF at room temperature to form the corresponding symmetrical and unsymmetrical diamino- to pentaaminotrisilanes in high yields, which are transformed into alkoxy and fluoro derivatives under mild conditions. A tetraaminotetrasilane has also been prepared by reductive homocoupling of (Et(2)N)Me(2)SiSiMe(NEt(2))Cl and converted into the alkoxytetrasilane. Some special experimental procedures have been employed for the selective coupling reactions.