A seven-membered-ring allene dimer: synthesis of 1,2-benzo-1,3,4-cycloheptatriene and attempted synthesis of 1,2-benzo-1,4,5-cycloheptatriene
摘要:
7,7-Dibromo-3,4-benzobicyclo[4.1.0]heptane (6) and 7,7-dibromo-2,3-benzobicyclo[4.1.0]heptane (14) have been synthesized and their silver ion-catalyzed reactions studied. Hydroxy alcohol 7a was converted to the corresponding vinyl bromide 10. Reaction of 10 with base gave the hydrocarbon 12, instead of the expected allene 4. Hydroxy alcohol 15a was converted to the corresponding mesylate 20, but all attempts to reduce 20 to the expected vinyl bromide 23 failed. Instead, unexpected ether 21 was obtained. Therefore, 15a was treated with PBr3 to give 22, which upon treatment with LiAlH4 gave the vinyl bromide 23. Reaction of 23 'with potassium tert-butoxide produced strained bicyclic allene 5, which underwent a dimerization to give 24. Addition of tetracyanoethylene to dimer 24 resulted in the formation of 26, whose structure was investigated by X-ray crystallography.
A seven-membered-ring allene dimer: synthesis of 1,2-benzo-1,3,4-cycloheptatriene and attempted synthesis of 1,2-benzo-1,4,5-cycloheptatriene
摘要:
7,7-Dibromo-3,4-benzobicyclo[4.1.0]heptane (6) and 7,7-dibromo-2,3-benzobicyclo[4.1.0]heptane (14) have been synthesized and their silver ion-catalyzed reactions studied. Hydroxy alcohol 7a was converted to the corresponding vinyl bromide 10. Reaction of 10 with base gave the hydrocarbon 12, instead of the expected allene 4. Hydroxy alcohol 15a was converted to the corresponding mesylate 20, but all attempts to reduce 20 to the expected vinyl bromide 23 failed. Instead, unexpected ether 21 was obtained. Therefore, 15a was treated with PBr3 to give 22, which upon treatment with LiAlH4 gave the vinyl bromide 23. Reaction of 23 'with potassium tert-butoxide produced strained bicyclic allene 5, which underwent a dimerization to give 24. Addition of tetracyanoethylene to dimer 24 resulted in the formation of 26, whose structure was investigated by X-ray crystallography.
A seven-membered-ring allene dimer: synthesis of 1,2-benzo-1,3,4-cycloheptatriene and attempted synthesis of 1,2-benzo-1,4,5-cycloheptatriene
作者:Y. Kemal Yildiz、Hasan Secen、Mariusz Krawiec、William H. Watson、Metin Balci
DOI:10.1021/jo00072a016
日期:1993.9
7,7-Dibromo-3,4-benzobicyclo[4.1.0]heptane (6) and 7,7-dibromo-2,3-benzobicyclo[4.1.0]heptane (14) have been synthesized and their silver ion-catalyzed reactions studied. Hydroxy alcohol 7a was converted to the corresponding vinyl bromide 10. Reaction of 10 with base gave the hydrocarbon 12, instead of the expected allene 4. Hydroxy alcohol 15a was converted to the corresponding mesylate 20, but all attempts to reduce 20 to the expected vinyl bromide 23 failed. Instead, unexpected ether 21 was obtained. Therefore, 15a was treated with PBr3 to give 22, which upon treatment with LiAlH4 gave the vinyl bromide 23. Reaction of 23 'with potassium tert-butoxide produced strained bicyclic allene 5, which underwent a dimerization to give 24. Addition of tetracyanoethylene to dimer 24 resulted in the formation of 26, whose structure was investigated by X-ray crystallography.