【摘要】 描述了一种基于二芳炔硫醚(Ar—C≡C—S—C≡C—Ar)底物合成2,6-二芳基-1,4-二噻烯的方法.将二芳炔硫醚和Na2S·9H2O在C2H5OH/C2H5ONa体系中回流反应,以80%~96%的产率合成了一系列2,6-二芳基-1,4-二噻烯化合物.该方法反应条件温和、产率高并且表现出很好的选择性.反应机理涉及硫负离子对底物分子的两个C≡C键的选择性亲核加成,即硫负离子(包括S2-和中间体B硫负离子)总是选择性地加到芳基一侧的炔碳上形成1,4-二噻烯.对化合物1a进行了X线晶体结构解析.分子中的六元杂环呈"船式"构型.C(1)—C(2)和C(1A)—C(2A)具有典型的双键性质,S(1)—C(2)和S(2)—C(1)的键长数则比一般C—S单键稍短,显示硫原子上的孤对电子与C(1)=C(2)双键上的π电子存在一定程度的共轭作用.1a的晶体学参数:属正交晶系,Pnma空间群,a=10.1330(11),b=27.318(3),c=5.5402(6),α=90.00°,β=90.00°,γ=90.00°,V=1533.6(3)3,Z=4,ρcalcd=1.422 g/cm3.最终偏离因子R=0.038,Rw=0.102。更多还原

【Abstract】 An effective preparation for 2,6-diaryl-1,4-dithiins(1) was accomplished by the reaction of bis(arylethynyl) sulfide(Ar—C≡C—S—C≡C—Ar) with Na2S·9H2O. The mild and simple method showed a good selectivity, and allowed the formation of 2,6-diaryl-1,4-dithiins(1) in up to 96% yields. A plausible mechanism for the reaction was also proposed. Thus, bis(arylethynyl) sulfide reacts with S2-, leading first to intermediate B, followed by addition of S anion in B to another C≡C bond to afford 1. The structure of 1a was unambiguously determined by X-ray analysis. 1a exhibited a six-membered hetero ring with boat conformation. The bond lengths of C(1)—C(2) and C(1A)—C(2A) are the typical characteristic of C=C double bond. S(1)—C(2) and S(2)—C(1) are slightly shorter than general C—S single bonds, indicating a certain degree of conjugation between the lone pair on the sulfur atom and π electrons of the C=C bond. Crystal data for 1a: orthorhombic, Pnma space group, a=10.1330(11) , b=27.318(3) , c=5.5402(6) , α=90.00°, β=90.00°, γ=90.00°, V=1533.6(3) 3, Z=4, ρcalcd=1.422 g/cm3. The final deviation factor R=0.038, Rw=0.102.更多还原