Reactions of Bis(trimethylsilyl)aminochlorosilanes with Lithium - N,Si- Migration of Trimethylsilylgroups or Self-condensation of Bis(trimethylsilyl) aminosilyllithium Compounds

摘要

The chlorosilanes [(Me _3Si) _2N]HMeSiCl (1), [(Me _3Si) _2N] _2MeSiCl (2) and [(Me _3Si) _2N]RPhSiCl (3: R = Me, 4: R = Ph, 5: R = (Me _3Si) _2N, 6: R = H) were allowed to react with lithium metal in tetrahydrofuran (THF) or in a mixture of THF/Et _2O-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 Me _3SiCl in molar ratio 1:1 reacted with lithium to give [(Me _3Si) _2N]HMeSi- SiMeH[N(SiMe _3) _2] (7) and [(Me _3Si) _2N]HMeSi-SiMe _3 (8). The analogous reaction of 2, Me _3SiCl and lithium afforded [(Me _3Si) _2N] _2MeSi-SiMe _3 (10) only. [(Me _3Si) _2N]MePhSiLi (11) and [(Me _3Si) _2N]Ph _2SiLi (16) prepared by reaction of 3 and 4 with lithium in THF underwent a partial rearrangement to form the lithium amides [(Li)(Me _3Si)N]MePhSi-SiMe _3 (12) and [(Li)(Me _3Si)N] Ph _2Si-SiMe _3 (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)(Me _3Si)N][(Me _3Si) _2N]PhSi-SiMe _3 (21) was formed. [(Me _3Si) _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 HMe _2SiCl resulting in the following products: [(Me _3Si) _2N]MePhSi-SiMe _2H (13), [(Me _3Si) _2N]Ph _2Si-SiMe _2H (18), [(Me _3Si) _2N] _2PhSi-SiMe _2H (24), [(HMe _2Si)(Me _3Si)N]MePhSi-SiMe _3 (14), [(HMe _2Si)(Me _3Si)N]Ph _2Si-SiMe _3 (19), and [(HMe _2Si)(Me _3Si)N][(Me _3Si) _2N]PhSi- SiMe _3 (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 [(Me _3Si) _2N]HPhSiLi (25) and [(Me _3Si) _2N]HPhSi-SiHPhLi (26) was obtained. Compounds 25 and 26 were trapped with HMe _2SiCl to give [(Me _3Si) _2N]HPhSi- SiMe _2H (27) and [(Me _3Si) _2N]HPhSi-SiHPh- SiMe _2H (28). The molecular structures of 19, 22 and 24 were determined.