Sübstitüebenzobarrelenlerin yeni ve uygun bir metodla sentezi

Abstract

3-Bromo~6,7-benzobisiklc okta-2,6-dienin -50°C de bromlanması^V/agner-Meervein düzenlenmesiyle anti-tribro-mo ürününü verdi. Bunun dehidrobrominasyonuyla 2-brombenzo-barrelen oluştu. 2-Brombenzobarrelene BuLi verdikten sonra, takiben ayrı ayrı CH^I, CO2 ve DMF ile muamele edildi. Bunlara tekabül eden bileşikler, benzobarrelenin metil, asit ve aldehit türevleri elde edildi. Asit türevinin diazometan ile reaksiyonundan da ester türevi sentezlendi. Böylece, monosübstitüebenzobarrelenlere yüksek verimli bir sentez yolu açıldı.Düzenlenmiş anti-tribromo katılma ürününden 1 mol HBr elimine ederek 2,5-dibromo~~7>8~benzobisiklo (2.2.2) okta-2,7-dien elde edildi. Bunun bromlanmasıyla meydana gelen katılma ürünlerinden 2 mol HBr ayrılmasıyla 2,3-dibromben-zobarrelen sentezlenerek, disubstitüebenzobarrelenlerin sentezine ilk defa uygun ve yüksek verimli bir yol bulundu.

Bromination of 3-bromo-6,7-benzobiciyclo[3.2,1] octa-2,6-diene at -50°C gave rearranged anti-tribro mo adduct in essentially quantitative yield. The double dehydrobromination of this was achieved using potassium tertv-Butoxide to give 2-bromo-benzobarrelene, After the treatment of 2-bro~ mo-benzobarrelene with CH^I» CO^ and Dimetylformamide afforded the methyl, carboxylic, acid and aldehyde derivatives respectively# Ester derivative was synthesized by the reac~ tion of the acid derivative with diazomethan, thus,for the synthesis of mono substituted benzobarrelenes, a method with a high yield was achieved,2,5-dibromo-7>8`benzobicyclo ¡2.2,2] octa-2,7-dien was obtained by elimination of one mol HBr from the rearrenged anti-tribromo compound. By bromination of this and subsequent elimination of 2 mols of HBr from its addition product,2,5-dgbromo-benzobarrelene was synthesized, As a result, an appropriate and efficient way of disubstitued benzobarrele-nes was described