Polylithium Compounds. IV. Polylithiation of Nitriles and the Preparations of Trisilyl Ynamines

摘要

Acetonitrile reacts with excess tert-butyllithium in ether at -78C to form Li2C2HN and 2 equiv of isobutane. With aldehydes and ketones, Li2C2HN gives diadducts, (LiOCR2)2CHCN, in high yields. These adducts are converted to the corresponding trimethylsilyl derivatives with trimethylchlorosilane. Li2C2HN, in the presence of excess base, and trimethylchlorosilane in tetrahydrofuran give a mixture of tris(trimethylsilyl)ethynylamine and tris-(trimethylsilyl)ketenimine. Li2C2HN also reacts with tert-butyldimethyl-chlorosilane and dimethylchlorosilane to give the corresponding trisilyl ynamines and ketenimines. Trisilyl ynamines undergo a quantitative thermal rearrangement to trisilyl ketenimines. Trimethylsilylacetonitrile and bis(trimethylsilyl)-acetonitrile react with n-butyllithium forming a dilithium derivative, Li2(Me3Si)C2N, and a monolithium derivative, Li(Me3Si)2C2N, respectively. The structures of the metalated nitriles were investigated by infrared spectroscopy. (Author)