Directed ortho Lithiation in the Reactions of 3,5-Dimethyl- and 5-Trifluoromethyl-1-phenylpyrazoles with Butyllithium

Article abstract of DOI:10.1246/cl.1992.357

Lithiation of 3,5-dimethyl- and 5-trifluoromethyl-1-phenylpyrazoles with butyllithium is found to be directed to an ortho position.The ortho direction is ascribed to coordination of lithium with pyrazole 2-nitrogen or 5-trifluoromethyl group, respectively.