论文信息 - 1,3-Dipolar Cycloaddition of Nitrile Imines with Functionalized Acetylenes: Regiocontrolled Sc(OTf)3-Catalyzed Synthesis of 4- and 5-Substituted Pyrazoles

1,3-Dipolar Cycloaddition of Nitrile Imines with Functionalized Acetylenes: Regiocontrolled Sc(OTf)3-Catalyzed Synthesis of 4- and 5-Substituted Pyrazoles

1,3-Dipolar cycloaddition of C-aryl-N-aryl- and C-carboxymethyl-N-aryl-nitrile imines with functionalized acetylenes have been studied. Regioisomeric mixtures have been obtained with the 5-substituted pyrazole as the major cycloadduct. Under scandium triflate catalysis a reversal in the regiochemistry was observed, especially in the case of C-carboxymethyl-N-aryl-nitrile imines.

M. Franchini | D. Gentili | E. Locatelli | B. Bonini | A. Ricci

[1] Alan R. Katritzky,et al. Handbook of heterocyclic chemistry , 1985 .

[2] A. Padwa. 1,3-Dipolar Cycloaddition Chemistry , 1984 .