Preparation and Structure of Alkenyl- and Alkynyl-Substituted Polysilamodules HC(SiMe<sub>2</sub>SiMe<sub>2</sub>)<sub>3</sub>CR
作者:Masaki Shimizu、Hirofumi Mizukoshi、Tamejiro Hiyama
DOI:10.1055/s-2004-822394
日期:——
Facile methods for the introduction of alkenyl and alkynyl groups at the bridgehead position of polysilamodule HC(SiMe2SiMe2)3CH are established. Deprotonation of the module with BuLi/t-BuOK in THF at -40 °C followed by alkylation with bromoacetaldehyde diethyl acetal gives the corresponding acetal, which was hydrolyzed with zinc chloride, yielding a formylmethyl-substituted cage compound. Treatment of the aldehyde with triflic anhydride in the presence of 2,6-di-t-butyl-3-methylpyridine produced the corresponding enol triflate consisting of a 4:1 mixture of E and Z isomers. Palladium-catalyzed cross-coupling of the triflate with organometallic reagents afforded alkenyl group-substituted cage molecules in good yields. Meanwhile, lithiation of phenylthio-substituted cage derivative with lithium 4,4′-di-tert-butylbiphenylide in THF followed by transmetalation with copper iodide and subsequent coupling with iodoalkynes allowed us to prepare alkynyl-substituted polysilacage compounds. The structures were determined by X-ray diffraction of single crystals.
建立了在多硅模块 HC(SiMe2SiMe2)3CH 的桥头位置引入烯基和炔基的简便方法。首先在 -40 °C 下用 BuLi/t-BuOK 在 THF 中去质子化该模块,然后用溴乙醛二乙基缩醛进行烷基化,得到相应的缩醛,随后用氯化锌水解,得到一种甲酰基甲基取代的笼状化合物。将该醛与三氟化酸酐在 2,6-二-叔丁基-3-甲基吡啶的存在下反应,生成相应的烯醇三氟甲基酯,包含 4:1 的 E 和 Z 异构体混合物。经过钯催化的三氟甲基酯与有机金属试剂的交叉耦合反应,获得了烯基取代的笼状分子,产率良好。同时,使用锂 4,4'-二叔丁基联苯负离子在 THF 中对苯硫取代的笼衍生物进行锂化,随后与碘化铜进行转金属化,再与碘炔进行耦合,成功制备了炔基取代的多硅笼化合物。通过单晶 X 射线衍射确定了这些结构。