Kemp decarboxylation
The Kemp decarboxylation is a name reaction in organic chemistry via a decarboxylation . It is the base-catalyzed ring opening of a benzisoxazole , which has a carboxy group on the C 3 atom. So it is a special case of Kemp elimination and was also named after the American chemist Daniel S. Kemp .
Overview reaction
The cleavage of the N – O bond leads to the ring opening of the 3-carboxybenzisoxazole . The ring opening is accompanied by decarboxylation. A phenol derivative is obtained as the product .
Reaction mechanism
The following mechanism is described in the literature:
The deprotonation of the benzisoxazole derivative 1 by a base leads to electron rearrangement. Carbon dioxide is therefore split off and the ring continues to open, creating the unstable intermediate stage 2 . The phenolate group of 2 is protonated by adding hydrochloric acid . This is how the phenol derivative 3 is formed .
Individual evidence
- ^ A b Zerong Wang: Comprehensive Organic Name Reactions and Reagents , Wiley, 2010, ISBN 9780470638859 , pp. 1605-1607, doi: 10.1002 / 9780470638859 .
- ↑ O. Acevedo and WL Jorgensen: Influence of inter- and intramolecular hydrogen bonding on Kemp decarboxylations from QM / MM simulations. In: Journal of the American Chemical Society 127, 2005, p. 8829, doi: 10.1021 / ja051793y .