Expedient synthesis of tetrasubstituted pyrroles via a copper-catalyzed cascade inter-/intramolecular cyclization of 1,3-enynes carry a nitro group with amines.

Expedient synthesis of tetrasubstituted pyrroles via a copper-catalyzed cascade inter-/intramolecular cyclization of 1,3-enynes carry a nitro group with amines.

Organic & biomolecular chemistry (2015-01-22)

Ganesan Bharathiraja, Mani Sengoden, Masanam Kannan, Tharmalingam Punniyamurthy

ABSTRACT

Various tetrasubstituted pyrroles/pyrazoles have been prepared from nitro-substituted 1,3-enynes with aromatic amines/hydrazines via a copper-catalyzed cascade aza-Michael addition, cyclization and aromatization at room temperature. This protocol is also effective for the synthesis of tetrasubstituted pyrazoles in high yields.

MATERIALS

Product Number

Brand

Product Description

741248

Sigma-Aldrich

Bis(triphenylphosphine)palladium(II) dichloride

93094

Sigma-Aldrich

Triphenylphosphine, polymer-bound, 100-200 mesh, extent of labeling: ~1-1.5 mmol/g Capacity (Phosphor)

03140

Sigma-Aldrich