The addition of dihalocarbenes to 1H-benzo[f]chromenes and 4H-chromenes gave a number of dihalotetrahydro(benzo)cyclopropa[b]-chromenes containing donor and acceptor substituents at different positions. It was found that in the case of 1,3-disubstituted 1H-benzo[f]-chromenes, the reaction proceeds diastereoselectively with the formation of trans-isomers. 12H,13H-7a,12a-Methanobenzo[f]indeno-[1,2-b]chromene and 12,13-dihydro-14H-7a,13a-methanodibenzo[a,h]xanthene, representatives of new heterocyclic systems, were obtained.

中文翻译：

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芳烃缩合的4 H-吡喃与二卤代卡宾的环丙烷化

向1 H-苯并[ f ]色烯和4 H-色烯中添加二卤卡宾，得到许多在不同位置含有供体和受体取代基的二卤四氢（苯并）环丙烷[ b ]-色烯。发现在1，3-二取代的1 H-苯并[ f ]-色烯的情况下，该反应非对映选择性地进行，形成反式异构体。12 H，13 H -7a，12a-甲基苯并[ f ]茚满-[1,2- b ]色烯和12,13-二氢-14 H -7a，13a-甲基二苯并[ a，h获得了新杂环系统代表的吨蒽。