Lewis acid- and/or Lewis base-catalyzed [3+2] cycloaddition reaction: synthesis of pyrazoles and pyrazolines

Palakodety Radha Krishna (1) , Empati Raja Sekhar (1)

1 Organic Chemistry Division-III

A facile, 1,3-dipolar cycloaddition of ethyl diazoacetate (EDA) with various activated olefins including Baylis-Hillman adducts, activated and simple alkynes to afford 3,5-disubstituted pyrazolines and pyrazoles respectively in moderate to good yields, in high regioselective manner in the presence of Indium chloride and/or DABCO is reported. All the reactions were carried out under no strong bases/acids, solvent free conditions and at ambient temperature to afford the heterocyclic compounds. Keywords: Ethyl diazoacetate, DABCO, Indium trichloride, activated olefins, Baylis- Hillman adducts, pyrazolines, pyrazoles.

Domaines: Chimie organique

Palakodety Radha Krishna, Empati Raja Sekhar. Lewis acid- and/or Lewis base-catalyzed [3+2] cycloaddition reaction: synthesis of pyrazoles and pyrazolines. Tetrahedron Letters, 2008, 49 (48), pp.6733-6936. ⟨10.1016/j.tetlet.2008.09.037⟩. ⟨hal-00783713⟩