Gomberg–Bachmann reaction
The Gomberg–Bachmann reaction, named for the Ukrainian-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 1 (here benzene) is coupled with base with the diazonium salt 2 to the biaryl 3 through an intermediate aryl radical. For example, p-bromobiphenyl may be prepared from 4-bromoaniline and benzene:[4]
- BrC6H4NH2 + C6H6 → BrC6H4−C6H5
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]
Pschorr reaction
One intramolecular variation which gives better results is the Pschorr reaction:[7][8][9]
The group Z can be CH2, CH2CH2, NH and CO (to fluorenone [10]) to name just a few.
See also
References
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- ↑ W. Pötsch. Lexikon bedeutender Chemiker (VEB Bibliographisches Institut Leipzig, 1989) (ISBN 3817110553)
- ↑ M. B. Smith, J. March. March's Advanced Organic Chemistry (Wiley, 2001) (ISBN 0-471-58589-0)
- ↑ Lua error in package.lua at line 80: module 'strict' not found.; Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
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- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Lua error in package.lua at line 80: module 'strict' not found.
- ↑ Review Article, Kenneth K. Laali and Mohammadreza Shokouhimehr, The Pschorr Reaction, a Fresh Look at a Classical Transformation Current Organic Synthesis, 2009, 6, 193–202. doi:10.2174/157017909788167275
- ↑ Lua error in package.lua at line 80: module 'strict' not found.