2-Vinyl- (2) and 3-vinyl[1]benzothieno[3,2-b]furan (3) react with dimethyl acetylenedicarboxylate, methyl propiolate, maleic anhydride, or acrylonitrile endo-selectively as dienes to afford new [1]benzothieno[3,2-b][1]benzofuran derivatives 7-20. cis-Anhydrides 13 and 18 were transformed into dimethyl esters 21 and 22, respectively. It was shown that the base-catalyzed hydrolysis of 13 and 18 is accompanied by rearrangement of double bond in 13 and cis/trans isomerization of carboxylic group. Diesters 21 and 22, and nitriles 20 and 24 were aromatized by treatment with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone. Selective monodecarboxylation of [1]benzothieno[3,2-b][1]benzofuran-8,9-dicarboxylic acid (26) and [1]benzothieno[3,2-b][1]benzofuran-6,7-dicarboxylic acid (27) afforded [1]benzothieno[3,2-b][1]benzofuran-8-carboxylic acid (28) and [1]benzothieno[3,2-b][1]benzofuran-7-carboxylic acid (29), respectively.
2-乙烯基-(2)和3-乙烯基[1]苯并噻吩[3,2-b]呋喃(3)与二甲基乙炔二羧酸二甲酯,丙炔酸甲酯,马来酸酐或丙烯腈进行[内]选择性地反应,作为双烯,形成新的[1]苯并噻吩[3,2-b][1]苯并呋喃衍生物7-20。[顺]酐13和18被转化为二甲酯21和22,分别。结果表明,[顺]酐13和18的碱催化水解伴随着[顺]双键的重排和羧基的[顺]/[反]异构化。二甲酯21和22以及腈20和24通过2,3-二氯-5,6-二氰-1,4-苯醌处理而芳香化。[1]苯并噻吩[3,2-b][1]苯并呋喃-8,9-二羧酸(26)和[1]苯并噻吩[3,2-b][1]苯并呋喃-6,7-二羧酸(27)的选择性单脱羧反应分别产生[1]苯并噻吩[3,2-b][1]苯并呋喃-8-羧酸(28)和[1]苯并噻吩[3,2-b][1]苯并呋喃-7-羧酸(29)。