Efficient Ce(III)-Catalyzed cis-Selective Synthetic Approach to γ-Lactones in Aqueous Media

Abstract

The first CeCl₃ · 7H₂O-catalyzed, one-pot synthesis of α-mercapto-γ-lactones via regioselective epoxide ring opening and mercaptoacetylative cyclization cascades in water is reported. The reaction between 2-methyl-2-phenyl-1,3-oxathiolan-5-one and a variety of terminal epoxides was carried out in aqueous media to afford γ-lactones in good to excellent yields (83–94%) with complete cis diastereoselectivity. Acetophenone obtained as a by-product was also recovered and recycled easily for further use.

GRAPHICAL ABSTRACT

Keywords:

• Aqueous medium
• CeCl₃ · 7H₂O
• diastereoselectivity
• epoxides
• γ-lactones

ACKNOWLEDGMENTS

We sincerely thank Indian Institute of Integrative Medicine (IIIM) Jammu and Sophisticated Analytical Instrumentation Facility (SAIF), Punjab University, Chandigarh, for providing microanalyses and spectra.

Notes

^a Time for completion of the reaction under MW irradiation.

^b Time for completion of the reaction at room temperature as indicated by TLC.

^c Yield of isolated and purified product 3a.

^a Refluxing time in water at room temperature.

^b Yield of isolated and purified products.

^c All compounds gave C, H, and N analyses within ±0.39%, and satisfactory spectral (IR, ¹H NMR, ¹³C NMR, and EIMS) data.