Bromination of ‘ endo ‐Benzocyclobutanorbornene': Synthesis of ‘ endo ‐ 11,12‐Dibromobenzocyclobutanorbornene': High‐Temperature Bromination, Part XIV

Abstract

The electrophilic addition of Br to −endo-benzocyclobutanorbornene× 5 at À 508 led in high yield to the formation of the rearranged dibromides 6 and 7. However, high-temperature bromination of 5 in decalin at 1508 gave exclusively nonrearranged product 8 in 98% yield. From the elimination of nonrearranged product 8, −endo-bromobenzocyclobutanorbornene× 9 and −endo-benzocyclobutanorbornene× 5 were obtained. Similarly, bromination of monobromide 9 at 778 yielded the nonrearranged tribromide 12 in quantitative yield. The dehydrobromination of 12 provided the −endo 11,12-dibromobenzocyclobutanorbornene× 3 in high yield, which is a synthon for the trimerization reactions.

One hundred years of benzotropone chemistry

“…To the best of those authors’ knowledge, this is the first synthesis of 23 . With the reaction conditions established, Balci’s group next turned their attention to evaluating the scope and limitations of the oxidation reaction with different types of benzo[7]annulene ( Scheme 56 ) [ 190 ]. Thus 8-bromo-5 H -benzo[7]annulene ( 329 ) was oxidized with different oxidants to give a mixture of bromobenzotropones such as 23 , 316 , and 26 .…”

High Temperature Bromination of Benzobicyclo[2.2.2]Octa-2,5-Diene Derivatives: Alternative Synthesis of Di-, Tri- and Tetra-Bromobenzobarrelenes

“…Increasing the temperature gives non-rearranged reaction products. [21][22][23][24][25][26][27][28] This factor encouraged us to raise the bromination temperature higher in order to obtain the non-rearranged bromination products derived from 5. For the high-temperature bromination reaction, a hot solution of bromine in CCl 4 was added directly to a refluxing solution of 5 in CCl 4 .…”

(1RS,2RS,3SR,4SR,9RS)-1,2,3,9-Tetrabromo-1,2,3,4-tetrahydro-1,4-methanonaphthalene

“…Besides industrial applications for these highly brominated compounds, such as pesticides, plastics, fire-retardants and pharmaceutical chemicals, they also play an important role as key compounds for the synthesis of other derivatives (Altundaş et al, 2002;Altundaş & Balcı, 1993). In this connection, great interest has been focused on the halogenation of benzonorbornadiene (Daştan et al, 1994(Daştan et al, , 2002Altundaş et al, 2000;Cristol & Nachtigall, 1967). As a continuation of our interest in this area, the structure of tetrabromide (3), which was prepared by published methods (Daştan & Balcı, 2005) starting from 2,9dibromobenzonorbornadiene, (1), by high-temperature bromination, is reported.…”