Reaktionen von Bis(trimethylsilyl)aminochlorsilanen mit Lithium – N, Si‐Trimethylsilylgruppenwanderung oder Selbstkondensation von Bis(trimethylsilyl)aminosilyllithiumverbindungen

Abstract

AbstractThe chlorosilanes [(Me3Si)2N]HMeSiCl (1), [(Me3Si)2N]2MeSiCl (2) and [(Me3Si)2N]RPhSiCl (3: R = Me, 4: R = Ph, 5: R = (Me3Si)2N, 6: R = H) were allowed to react with lithium metal in tetrahydrofuran (THF) or in a mixture of THF/Et2O/n‐pentane in the volume ratio 4:1:1 (Trapp mixture). 1 and 2 did not react with lithium in THF at room temperature. A mixture of 1 and Me3SiCl in molar ratio 1:1 reacted with lithium to give [(Me3Si)2N]HMeSi–SiMeH[N(SiMe3)2] (7) and [(Me3Si)2N]HMeSi–SiMe3 (8). The analogous reaction of 2, Me3SiCl and lithium afforded [(Me3Si)2N]2MeSi–SiMe3 (10) only. [(Me3Si)2N]MePhSiLi (11) and [(Me3Si)2N]Ph2SiLi (16) prepared by reaction of 3 and 4 with lithium in THF underwent a partial rearrangement to form the lithium amides [(Li)(Me3Si)N]MePhSi–SiMe3 (12) and [(Li)(Me3Si)N]Ph2Si–SiMe3 (17), respectively, when the temperature raised from –78 °C to room temperature. In the reaction of 5 with lithium in THF at –78 °C, the amide [(Li)(Me3Si)N][(Me3Si)2N]PhSi–SiMe3 (21) was formed. [(Me3Si)2N]2PhSiLi (20) was obtained by reaction of 5 with lithium in the Trapp mixture at –110 °C. The silyllithiums 11, 16, 20 and the lithium amides 12, 17, 21 were trapped with HMe2SiCl resulting in the following products: [(Me3Si)2N]MePhSi–SiMe2H (13), [(Me3Si)2N]Ph2Si–SiMe2H (18), [(Me3Si)2N]2PhSi–SiMe2H (24), [(HMe2Si)(Me3Si)N]MePhSi–SiMe3 (14), [(HMe2Si)(Me3Si)N]Ph2Si–SiMe3 (19), and [(HMe2Si)(Me3Si)N][(Me3Si)2N]PhSi–SiMe3 (22). The silyllithiums 11, 16, and 20 were formed directly by reaction of the corresponding aminochlorosilanes with lithium at –78 °C (11 and 16) and at –110 °C (20), respectively. In the reaction of the aminochlorosilane 6 with lithium in THF at –78 °C a mixture of [(Me3Si)2N]HPhSiLi (25) and [(Me3Si)2N]HPhSi–SiHPhLi (26) was obtained. Compounds 25 and 26 were trapped with HMe2SiCl to give [(Me3Si)2N]HPhSi–SiMe2H (27) and [(Me3Si)2N]HPhSi–SiHPh–SiMe2H (28). The molecular structures of 19, 22 and 24 were determined.