Approach to Synthesis of β-Enamino Ketones and Pyrroles Catalyzed by Gallium(III) Triflate Under Solvent-Free Conditions

Abstract

Metal triflates have been used to catalyze synthesis of β-enamino ketones or pyrroles from amines and 1,3-dicarbonyl or 1,4-dicarbonyl compounds under solvent-free conditions, respectively. Among different metal triflates screened, 0.5 mol% Ga(OTf)₃ efficiently promoted the reactions to give excellent yields. In addition, the catalyst could be recovered easily after the reactions and reused without evident loss in activity.

Keywords:

• β-Enamino ketones
• gallium(III) triflate
• pyrroles
• solvent-free conditions

ACKNOWLEDGMENTS

We are grateful to the National Natural Science Foundation of China (No. 20676123 and 20476098) and Natural Science Foundation of Zhejiang Province (No. Y405015) for financial support.

Notes

^a 30°C for 25 min.

^b Isolated yield.

^c Catalyst was reused three times.

^d Reaction was run at 50°C for 12 h.

^a Reaction conditions: amine (5 mmol), acetylacetone (5 mmol), and Ga(OTf)₃ (0.5 mol%), 30°C.

^b Isolated total yield.

^c Reaction was run for 2 h.

^a Reaction conditions: amine (5 mmol), acetonylacetone (5 mmol), and Ga(OTf)₃ (0.5 mol%), 30°C.

^b Isolated total yield.