Synthesis and Properties of a Kinetically Stabilized 9-Silaphenanthrene
2007; American Chemical Society; Volume: 26; Issue: 16 Linguagem: Inglês
10.1021/om700347z
ISSN1520-6041
AutoresNorihiro Tokitoh, A. Shinohara, Takeshi Matsumoto, Takahiro Sasamori, Nobuhiro Takeda, Yukio Furukawa,
Tópico(s)Organoboron and organosilicon chemistry
ResumoReaction of 9-bromo-9,10-dihydro-9-silaphenanthrene (6) with lithium diisopropylamide (LDA) in THF at room temperature afforded kinetically stabilized 9-silaphenanthrene 1a bearing an efficient steric protection group, 2,4,6-tris[bis(trimethylsilyl)methyl]phenyl (Tbt). 9-Silaphenanthrene 1a was isolated as pale yellow crystals, and the structure of 1a was completely determined by spectroscopic and X-ray crystallographic analyses. The 1H and 13C NMR chemical shifts corresponding to the 9-silaphenanthrene ring of 1a were observed in a typical aromatic region, while the central silicon atom showed the characteristic signal at 86.9 ppm in the 29Si NMR in C6D6. The 9-silaphenanthrene ring of 1a showed completely planar geometry, indicating that 9-silaphenanthrene has a delocalized 14π-electron system as an aromatic compound. In spite of its high thermal stability, 1a still has high reactivity at the 9,10-position toward small reagents such as H2O.
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