Asymmetric synthesis of (–)-leiocarpin A via (–)-(S)-goniothalamin employing Julia–Kocienski olefination

ABSTRACT

A concise and enantioselective syntheses of antileukemic natural products such as (–)-(S)-goniothalamin and (–)-leiocarpin A has been accomplished in excellent yields. By employing reported conditions on suitable substrates via Julia–Kocienski olefination, intramolecular lactonization, and subsequently dehydroxylative olefination, (–)-(S)-goniothalamin was synthesized. Then Sharpless asymmetric dihydroxylation–intramolecular Michael addition on (–)-(S)-goniothalamin provided (–)-leiocarpin A.

GRAPHICAL ABSTRACT

KEYWORDS:

• Acetonide deprotection
• Julia–Kocienski olefination
• lactonization
• Michael addition
• saturated and unsaturated pyranone
• sharpless asymmetric dihydroxylation

Acknowledgments

S. B. Meruva, M. Asif, and R. R. Kamaraju thank Dr. H. Rama Mohan of Dr. Reddy’s Laboratories Ltd. for his encouragement and Dr. J. Moses Babu of analytical department for the analytical support.