Syntheses of Acetylenes Substituted with Heteroaromatic Containing Trifluoromethyl Groups

1. 试图用四氟化硫氟化呋喃、噻吩和n -甲基吡咯等杂芳烃的2羧酸，得到只含柏油的聚合材料。然而，呋喃和噻吩的2,5-二羧酸通过与四氟化硫氟化反应得到2,5-二（三氟甲基）呋喃和噻吩以及相应的杂芳烃的5-三氟甲基- 1-2羧酸。2-三氟甲基-5-羧酸在铜粉存在下加热脱羧，合成了2-三氟甲基呋喃和噻吩。含三氟甲基的氟化呋喃和噻吩用1,1-二氯-2,2-二氟乙烯处理，得到相应的含1-氟-2,2-二氯乙烯基的呋喃和噻吩，然后用正丁基锂脱卤转化为乙基。用WC1_6-Ph_4Sn等催化剂聚合了几种三氟甲基取代呋喃和带乙基的噻吩，得到了相应的聚乙炔。2,5-二（三氟甲基）-3-乙基呋喃和噻吩被发现可以得到高分子量的聚乙炔。

1. Fluorination of 2-carboxylic acids of heteroaromatics, such as furan, thiophene and N-methylpyrrole, by sulfur tetrafluoride were attempted to give only, tarry polymeric materials. 2,5-Dicarboxylic acids of furan and thiophene, however, afforded 2,5-bis (trifluoromethyl) furan and thiophene together with 5-trifluoromethy1-2-carboxylic acids of the corresponding heteroaromatics by fluorination with sulfur tetrafluoride. 2-Trifluoromethylfuran and thiophene were synthesized by decarboxylation of the 2-trifluoromethyl-5-carboxylic acids on heating in the presence of copper powder.2. The lithiated furans and thiophenes containing trifluoromethyl groups were treated with 1,1-dichloro-2,2-difluoroethylene to give the corresponding furans and thiophenes with a 1-fluoro-2,2-dichlorovinyl group, which was then converted to a ethynyl group by dehalogenation with n-butyllithium.3. Several trifluoromethyl-substituted furans and thiophenes with a ethynyl group were polymerized using a catalyst such as WC1_6-Ph_4Sn, to yield the corresponding polyacetylenes. 2,5-Bis (trifluoromethyl)-3-ethynylfuran and thiophene were found to give a high molecular weight polyacetylenes.