First synthesis, X-ray structure analysis and reactions of alkenyltriphenylbismuthonium salts
作者:Yoshihiro Matano、Masanori Yoshimune、Nagao Azuma、Hitomi Suzuki
DOI:10.1039/p19960001971
日期:——
Treatment of triphenylbismuth difluoride with alkenyltrimethylsilanes 1 or trimethylsilyl cyanide–alkenyltrialkylstannanes 3 in the presence of boron trifluoride–diethyl ether gave the corresponding alkenyltriphenylbismuthonium tetrafluoroborates 2 in moderate to good yields. An X-ray crystallographic analysis of the salt 2e confirmed the distorted tetrahedral geometry of the central bismuth atom. When treated with a sulfinate 5 or the thiolate 11, the salts 2 readily transferered both the vinyl and phenyl moieties to these nucleophiles to afford the sulfones 7–10 or the sulfides 12, 13, respectively. In the presence of a palladium catalyst, the salt 2e underwent the Heck-type reaction with ethyl acrylate 17 to afford the dienoate 18 and cinnamate 19 in moderate yields. Action of KOBut on the salt 2b yielded p-tolylacetylene 22, while a similar reaction with the salt 2e in the presence of the styrenes 23 gave the cyclopropanes 24. A Hammett study of the latter reaction has suggested a possible involvement of an alkylidenecarbene as the intermediate in these base-promoted reactions.
三苯基二氟化铋与烯基三甲基硅烷1或三甲基硅氰基-烯基三烷基锡烷3在三氟化硼-乙醚存在下反应,以中等至良好收率得到相应的烯基三苯基铋鎓四氟硼酸盐2。盐2e的X射线晶体学分析证实了中心铋原子扭曲的四面体几何结构。当与亚砜5或硫醇盐11处理时,盐2容易将乙烯基和苯基部分转移到这些亲核试剂上,分别得到砜7-10或硫化物12、13。在钯催化剂的存在下,盐2e与丙烯酸乙酯17发生 Heck 型反应,以中等收率得到二烯酸酯18和肉桂酸酯19。KOBut 对盐2b的作用产生了对甲苯乙炔22,而在苯乙烯23的存在下,盐2e的类似反应得到了环丙烷24。后一反应的 Hammett 研究表明,这些碱促进的反应中可能涉及一个烯基碳烯中间体。