Synthesis of 1-Cyclohept-1,2-dien-1-yl Benzene from 1-(2-iodo-, chlorocyclohept-1-en-1-yl)benzene and 1-(2-iodo-, chlorocyclohept-2-en-1-yl)benzene: Its Trapping with Diphenylisobenzofuran

Authors : Mustafa CEYLAN, Yakup BUDAK, Murat ULUKAYA

Pages : 663-672

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Publication Date : 0000-00-00

Article Type : Research Paper

Abstract :The key compounds vinyl iodides 12a and 13a, for the generation of 1-cyclohept-1,2-dien-1-ylbezene insert ignore into journalissuearticles values(1);, were synthesized from cycloheptanone insert ignore into journalissuearticles values(5);. Bromobenzene was converted to the Grignard reagent, which was condensed with 5. Dehydration of alcohol 6 gave alkene 7. Hydroboration of 7 followed by oxidation with PCC afforded ketone 9, which was converted to hydrazone 10. Treatment of 10 with iodine resulted in the formation of 12a and 13a. The other precursors, 12b and 13b, were synthesized from the reaction of 9 with PCl5. Reactions of 12a, b and 13a, b with KOtBu in a sealed tube at 185 °C gave the [2+4] and [2+2] dimer products 20 and 21, respectively. In addition, reactions of 12a, b and 13a, b with KOtBu under the same conditions in the presence of diphenylbenzoisofuran insert ignore into journalissuearticles values(DBI); as a trapping reagent afforded the [2+4] cycloadducts 24 and 25 in good yields.
Keywords : Substituted cyclic allene, dehydroiodination, dehydrochloration, dimerization, cycloaddition