Journal of the Chemical Society. Perkin transactions I p. 3225 - 3233 (1981)
Update date:2022-08-04
Topics:
Bradbury, Robert H.
Gilchrist, Thomas L.
Rees, Charles W.
A synthesis of ethyl 4-methoxy-4a-methyl-4aH-benzocycloheptene-5-carboxylate (12), the first isolable 4aH-benzocycloheptene, is described.The skeleton is constructed by Cope rearrangement of the divinyl-cyclopropane (8).Further unsaturation is then introduced by the use of dichlorodicyanobenzoquinone to give the tetraenone (10), from which an extended enolate anion is generated by means of sodium hydride in 1,2-dimethoxyethane.O-Methylation of the anion gives the ether (12).At 138 deg C this compound undergoes unimolecular skeletal rearrangement and gives a mixture of three products.It is proposed that these are formed from a common bisnorcaradiene intermediate (17).A new type of rearrangement, which involves the conversion of the bis-norcaradiene (17) into a second bis-norcaradiene by a (?28 + ?4a + ?4a) process, is suggested to explain the formation of the product (19).The methoxy-ester (12) also undergoes 4 + 2 cycloaddition with 4-phenyl-1,2,4-triazolinedione and an acid-catalysed methyl group migration. 4-Methoxy-4a-methyl-4aH-benzocycloheptene (28) has been generated by a analogous route; at room temperature this undergoes skeletal rearrangement, of the same type as observed with the ester (12).
View MoreWuhan Chemchemical Co., Ltd.(expird)
Contact:15973022782
Address:7-5-6218,Incubation Centre,Guandong Industry Park, East Lake High-Tech Development Zone,Wuhan City.
Contact:0571-
Address:zhejing
website:http://www.vanzpharm.com/en/index.html
Contact:86-27-84492310
Address:FANHU INDUSTRY PARK
Sichuan Highlight Fine Chemicals Co., Ltd.
Contact:+86-28-8525 1605
Address:A5-102 Airport base,388 West Airport Huang He Zhong Lu,2 Section
Hangzhou Showland Technology Co., Ltd.
Contact:86-571-88920516
Address:ROOM2118,NO.553,WENSAN ROAD,HANGZHOU,CHINA
Doi:10.1021/ic049799w
(2004)Doi:10.1016/S0022-328X(00)94408-5
(1980)Doi:10.1021/ja00522a054
(1980)Doi:10.1016/j.tetlet.2005.08.017
(2005)Doi:10.1016/S0040-4020(01)82988-4
(1969)Doi:10.1016/S0040-4039(01)91387-5
(1984)
