摘要:
Treatment of (RH2C)(2)C5H3N-2,6 (R = SiMe3) with Bu"Li followed by addition of Me3SiCl gave the tetrasilyl pyridine derivative (R2HC)(2)C5H3N-2,6 1 in high yield. Further lithiation of 1 with Bu"Li and reaction of the intermediate with PhCN led to the new lithium-1-azaallyl [Li{N(R)C(Ph)C(R)(C5H3N-2,6)(CHR2)}](2) 2, while metallation of the previously described di-lithium compounds [Li{N(R)C(R')CH}(2)(C5H3-2,6)]Li(tmen)(n) (R = SiMe3, R' = Bu', n = 1 or R = SiMe3, R' = Ph, n = 2) with PdCl2(PhCN)(2) yielded the novel metallacycles [Pd{{N(H)(R)C(R')CH} {N(SiMe2CH2)C(R')CH}C5H3N-2,6}] 3 (R' = Bu') and [Pd{{N(R)C(R')CH}{N(R)-(H)C(R')CH} C5H3N-2,6}(2)] (R' = Ph) 4 in moderate to low yield. Compound 3 is unusual in being the first example of a crystallographically characterised PdNSiC heterocycle which is believed to be formed via an intramolecular CH-activation of a trimethylsilyl group by Pd(II). All four compounds were fully characterised by NMR-spectroscopy, microanalysis (not 4) and X-ray diffraction. (C) 2004 Elsevier B.V. All rights reserved.