Gomberg–Bachmann reaction | |
---|---|
Named after |
Moses Gomberg Werner Emmanuel Bachmann |
Reaction type | Coupling reaction |
The Gomberg–Bachmann reaction, named for the Russian-American chemist Moses Gomberg and the American chemist Werner Emmanuel Bachmann, is an aryl-aryl coupling reaction via a diazonium salt. [1] [2] [3]
The arene compound (here benzene) is reacted with a diazonium salt in the presence of a base to provide the biaryl through an intermediate aryl radical. For example, p-bromo biphenyl may be prepared from 4-bromoaniline and benzene: [4]
The reaction offers a wide scope for both diazonium component and arene component but yields are generally low following the original procedure (less than 40%), given the many side-reactions of diazonium salts. Several improvements have been suggested. One possibility is to employ diazonium tetrafluoroborates in arene solvent together with a phase-transfer catalyst, [5] another is to use 1-aryl-3,3-dialkyltriazenes. [6]
One intramolecular variation which gives better results is the Pschorr cyclization: [7] [8] [9]
The group Z can be CH2, CH2CH2, NH and CO (to fluorenone [10]) to name just a few.
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
Gomberg–Bachmann reaction | |
---|---|
Named after |
Moses Gomberg Werner Emmanuel Bachmann |
Reaction type | Coupling reaction |
The Gomberg–Bachmann reaction, named for the Russian-American chemist Moses Gomberg and the American chemist Werner Emmanuel Bachmann, is an aryl-aryl coupling reaction via a diazonium salt. [1] [2] [3]
The arene compound (here benzene) is reacted with a diazonium salt in the presence of a base to provide the biaryl through an intermediate aryl radical. For example, p-bromo biphenyl may be prepared from 4-bromoaniline and benzene: [4]
The reaction offers a wide scope for both diazonium component and arene component but yields are generally low following the original procedure (less than 40%), given the many side-reactions of diazonium salts. Several improvements have been suggested. One possibility is to employ diazonium tetrafluoroborates in arene solvent together with a phase-transfer catalyst, [5] another is to use 1-aryl-3,3-dialkyltriazenes. [6]
One intramolecular variation which gives better results is the Pschorr cyclization: [7] [8] [9]
The group Z can be CH2, CH2CH2, NH and CO (to fluorenone [10]) to name just a few.
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)
{{
cite journal}}
: CS1 maint: multiple names: authors list (
link)