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  • 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

Copper(I) iodide ChemBeads
Sigma-Aldrich
Bis(triphenylphosphine)palladium(II) dichloride
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Copper(I) chloride, AnhydroBeads, ≥99.99% trace metals basis
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Bis(triphenylphosphine)palladium(II) dichloride
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Triphenylphosphine, polymer-bound, 100-200 mesh, extent of labeling: ~1-1.5 mmol/g Capacity (Phosphor)
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Copper(I) iodide, purum, ≥99.5%
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Copper(I) iodide, 99.999% trace metals basis
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Copper(I) chloride, ≥99.995% trace metals basis
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Bis(triphenylphosphine)palladium(II) dichloride, 98%
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Copper(I) iodide, anhydrous, 99.995% trace metals basis
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Copper(I) iodide, 98%
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Copper(I) chloride, ReagentPlus®, purified, ≥99%
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Triphenylphosphine, ReagentPlus®, 99%
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Triphenylphosphine, ≥95.0% (GC)