A Convenient Synthesis of 1,2-Dithietes and 1,2-Dithioxo Compounds Stabilized by Buttressing and Resonance Effects, Respectively, by Sulfuration of Alkynes with Elemental Sulfur
作者:Keun Soo Choi、Isao Akiyama、Masamatsu Hoshino、Juzo Nakayama
DOI:10.1246/bcsj.66.623
日期:1993.2
Sulfuration of a series of alkynes by elemental sulfur was investigated. Alkynes carrying highly bulky substituents, 2,2,5,5-tetramethyl-3-hexyne (6a), 1,2-di-(1-adamantyl)ethyne (6b), 3,3-dimethyl-1-phenyl-1-butyne (6c), and 1-(1-adamantyl)-2-phenylethyne (6d), reacted with sulfur to give the corresponding stable 1,2-dithietes 7a—d in 46—65% yields. Less hindered alkynes reacted with sulfur to afford 1,4-dithiins and thiophenes as the final products which were derived from the initial products, 1,2-dithietes, via their tautomerization to the corresponding 1,2-dithioxo compounds, while extremely congested alkynes failed to react with sulfur even under forcing conditions. On the other hand, ynamines, a typical electron-rich alkyne, 1-diethylamino-2-phenylthioethyne (6o), 1-diethylamino-2-phenylselenoethyne (6p), and tetraethylethynediamine (6q) were sulfurated under milder conditions to afford resonance-stabilized 1,2-dithioxo compounds 19o—q as the principal products. Mechanism of the formation of 1,2-dithietes, 1,2-dithioxo compounds, and other products is discussed.
用元素硫对一系列炔烃进行硫化反应进行了研究。带有高度庞大取代基的炔烃,2,2,5,5-四甲基-3-己炔(6a)、1,2-双(1-金刚烷基)乙炔(6b)、3,3-二甲基-1-苯基-1-丁炔(6c)和1-(1-金刚烷基)-2-苯乙炔(6d),与硫反应得到相应的稳定1,2-二硫杂环己烯7a—d,产率为46—65%。取代基较少的炔烃与硫反应得到1,4-二硫杂苯和噻吩作为最终产物,这些产物由初始产物1,2-二硫杂环己烯通过其互变异构化形成相应的1,2-二硫氧化物得到,而极其拥挤的炔烃即使在强制条件下也无法与硫反应。另一方面,典型的富电子炔烃亚胺,1-二乙氨基-2-苯硫乙炔(6o)、1-二乙氨基-2-苯硒乙炔(6p)和四乙基乙炔二胺(6q),在较温和的条件下被硫化得到共振稳定的1,2-二硫氧化物19o—q作为主要产物。讨论了1,2-二硫杂环己烯、1,2-二硫氧化物和其他产物的形成机理。