Enantioselective Total Synthesis of (+)-EBC-23, a Potent Anticancer Agent from the Australian Rainforest
Year: 2021
Type: article
Abstract: We describe here an enantioselective synthesis of (+)-EBC-23, a potent anticancer agent from the Australian rainforest. Our convergent synthesis features a [3+2] dipolar cycloaddition of an olefin-bearing 1,3- syn diol unit and an oxime segment containing 1,2- syn diol functionality as the key step. The segments were synthesized in a highly enantioselective manner using Noyori asymmetric hydrogenation of a β-keto ester and Sharpless asymmetric dihydroxylation of an α,β-unsaturated ester. Cycloaddition provided isoxazoline derivative which upon hydrogenolysis furnished the β-hydroxy ketone expediently. A one-pot, acid-catalyzed reaction removed the isopropylidene group, promoted spirocyclization, constructed the complex spiroketal lactone core, and furnished EBC-23 and its C11 epimer. The C11 epimer was also converted to EBC-23 by chemoselective oxidation and reduction sequence. The present synthesis provides convenient access to this family of natural products in an efficient manner.
Source: The Journal of Organic Chemistry
Authors: Arun K. Ghosh, Che-Sheng Hsu
Institution: Purdue University West Lafayette
Language: English
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W3153548610