N-aryl pyrazoles: DFT calculations of CH acidity and deprotonative metallation using a combination of lithium and zinc amides.

Floris Chevallier (1) , Yury S. Halauko (2) , Christelle Pecceu (1) , Ibrahim F. Nassar (1) , To Uyen Dam (1) , Thierry Roisnel (3) , Vadim E. Matulis (4) , Oleg A. Ivashkevich (4) , Florence Mongin (1)

1 CPM - Chimie et Photonique Moléculaires
2 Department of electrochemistry
3 ISCR - Institut des Sciences Chimiques de Rennes
4 Research Institute for Physico-Chemical Problems

A series of N-aryl and N-heteroaryl pyrazoles have been deproto-metallated using a 2,2,6,6-tetramethylpiperidino-based mixed lithium-zinc combination. Mono-, di-, and tri-iodides have been obtained after subsequent trapping with iodine, depending on the substrate and on the quantity of base used. The results have been discussed in the light of the CH acidities of the substrates, determined both in the gas phase and in THF solution using the DFT B3LYP method.

Domaines: Chimie organique

Floris Chevallier, Yury S. Halauko, Christelle Pecceu, Ibrahim F. Nassar, To Uyen Dam, et al.. N-aryl pyrazoles: DFT calculations of CH acidity and deprotonative metallation using a combination of lithium and zinc amides.. Organic & Biomolecular Chemistry, 2011, 9 (12), pp.4671-4684. ⟨10.1039/c1ob05267e⟩. ⟨hal-00737022⟩