Concise Total Synthesis of (−)-Erinapyrone B from D-(+)-Malic Acid

Abstract

A convenient and facile enantioselective synthesis of (−)-erinapyrone B from commercially available D-(+)-malic acid has been achieved in seven steps. One of the key steps in this synthesis was the one-pot reaction of palladium(II)-mediated Wacker-type oxidative cyclization in the presence of a catalytic amount of p-toluenesulphonic acid (p-TsOH) which has been found to be effective for the preparation of enantiopure 2,3-dihydro-4H-pyran-4-one from the corresponding enantiopure β-hydroxyenone via enantio-enriched diketohydroxy intermediate.

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GRAPHICAL ABSTRACT

Keywords:

• 2,3-Dihydro-4H-pyran-4-one
• β-hydroxyenone
• oxidative cyclization
• Pd-catalyzed
• p-TsOH

ACKNOWLEDGMENTS

The authors are grateful to GVK Biosciences Pvt. Ltd. for the financial support and encouragement. We thank Subhabrata Sen for his immense assistance.