Written by J.A Dobado | Last Updated on September 15, 2025
What is Borsche-Drechsel cyclization?
The Borsche-Drechsel cyclization is a chemical process that involves the transformation of cyclohexanone phenylhydrazone into tetrahydrocarbazole through an acid-catalyzed rearrangement.
This rearrangement is followed by an oxidation step, resulting in the formation of carbazole.
References
- Drechsel, E. (1888), Ueber Elektrolyse des Phenols mit Wechselströmen. [On the electrolysis of phenol with alternating currents.] J. Prakt. Chem., 38: 65-74. https://doi.org/10.1002/prac.18880380105
- Borsche, W. and Feise, M. (1907), Über einige neue Carbazolderivate. [On some new carbazole derivatives] Ber. Dtsch. Chem. Ges., 40: 378-386. https://doi.org/10.1002/cber.19070400161
- Borsche, W. (1908), Ueber Tetra- und Hexahydrocarbazolverbindungen und eine neue Carbazolsynthese. (Mitbearbeitet von. A. Witte und W. Bothe.). [On tetra- and hexahydrocarbazole compounds and a new carbazole synthesis. (Co-edited by. A. Witte and W. Bothe.)] Justus Liebigs Ann. Chem., 359: 49-80. https://doi.org/10.1002/jlac.19083590103
Full Professor of Organic Chemistry at the University of Granada, with a long-standing research career in Computational Chemistry and molecular modeling and design.