8-tetrahydrothieno[2,3-f]benzofuran-6-carboxylates (2). Cerium(IV) ammonium nitrate (CAN)-mediated cycloaddition of ethyl 5-hydroxy-4,7-dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylates (1) to alkenes or phenylacetylene, giving ethyl 4,8-dioxo-4,8-dihydrothieno[2,3-f]benzofuran-6-carboxylate (2 or 4) and ethyl 4,5-dioxo-4,5-dihydrothieno[3,2-g]benzofuran-7-carboxylate derivatives (3 or 5), is also reported.
5-hydroxy-3-methyl-4,7-dioxo-4,7-dihydrobenzo[b]thiophene-2-carboxylate (la) 和烯烃之间的光诱导环加成反应生成 7-methyl-4,8-dioxo
乙酯-2,3,4,8-
四氢噻吩并[2,3-f]
苯并呋喃-6-羧酸盐 (2)。
铈 (IV)
硝酸铵 (CAN) 介导 5-羟基-4,7-二氧代-4,7-二氢苯并[b]
噻吩-2-
羧酸乙酯 (1) 与烯烃或
苯乙炔的环加成反应,得到 4,8
乙酯-dioxo-4,8-dihydrothieno[2,3-f]benzofuran-6-carboxylate(2 或 4)和 4,5-dioxo-4,5-dihydrothieno[3,2-g]benzofuran-7-carboxylate还报告了衍
生物(3 或 5)。