Journal of Organic Chemistry p. 1834 - 1840 (1983)
Update date:2022-07-29
Topics:
Padwa, Albert
Kumagai, Tsutomu
Tohidi, Mahrokh
A study of the reactivity of 2-diazopropane with a series of diphenyl-substituted cyclopropenes has been carried out.The cycloadditions afford 1,5-diphenyl-2,3-diazabicyclo<3.1.0>hex-2-enes in high yield.Thermolysis of the diazabicyclohexene system for extended periods of time afforded a mixture of 1,3-dienes as well as a substituted bicyclo<1.1.0>butane.By studying the distribution of products as a function of time it was possible to show that the 2,3-diazabicyclohexene system first rearranges to an isomeric 1,2-diazabicyclo<3.1.0>hex-2-ene.This reaction was attributed to an initial <3+2> cycloreversion to produce a diazoalkene.Attack of the terminal nitrogen atom of the initially generated diazo group onto the neighboring double bond affords the bicyclic aziridine system.Reasonable mechanistic options for the 1,1-cycloaddition include a concerted pathway or a stepwise process.On further heating the 1,2-diazabicyclohexene ring regenerates the allyl-substituted diazoalkane.Loss of nitrogen produces a carbene which undergoes a hydrogen or vinyl shift to give the observed dienes.The formation of the bicyclo<1.1.0>butane ring can be viewed in terms of a process involving initial C-N bond cleavage of the 2,3-diazabicyclohexene to yield a diazenyl radical followed by nitrogen loss and radical coupling.In contrast to the thermal results, direct irradiation of the 2,3-diazabicyclohexene results in a <4+2> cycloreversion to give a 3,4-diaza-substituted 1,3,5-hexatriene derivative.The results obtained indicate that the total mechanistic picture for the thermal and photochemical decomposition of bicyclic pyrazolines can be changed dramatically by the presence of phenyl substituents.
View MoreRongCheng Tianyu Technology Co.,Ltd.
Contact:86-631-7519595
Address:220Ping Donghai Road RongChengCity,ShangDong Province China
Shouguang Nuomeng Chemical Co., Ltd.
Contact:+86-536-5119508/18363669993
Address:Hou Zhen Industrial Park, Shouguang, Shandong, China
Hangzhou Maytime Bio-Tech Co.,Ltd.
website:http://www.maytime.com.cn
Contact:+86-571-88925295 88920965
Address:NO.2-1701 Ganghui Central Ningwei Street, Xiaoshan Hangzhou Zhejiang China
Contact:86-571-86737118-8689
Address:No.69, 12 Street, HEDA, Hangzhou, Zhejiang, China
Fujian Wanke Pharmaceutical Co., LTD.
Contact:+86-598-5026002
Address:Economic development zone,jiangle county
Doi:10.1021/op049822x
(2005)Doi:10.1021/ja01145a151
(1951)Doi:10.1002/adsc.200600367
(2006)Doi:10.1007/BF02900472
(1927)Doi:10.1021/ja01855a504
(1941)Doi:10.1016/j.tetasy.2005.03.015
(2005)