Volume 61, Issue 24 e202203239
Communication

Total Synthesis of Starfish Cyclic Steroid Glycosides

Dr. Dapeng Zhu

Dr. Dapeng Zhu

State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032 China

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Mingyu Geng

Mingyu Geng

State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032 China

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Prof. Biao Yu

Corresponding Author

Prof. Biao Yu

State Key Laboratory of Bioorganic and Natural Products Chemistry, Center for Excellence in Molecular Synthesis, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, 200032 China

School of Chemistry and Materials Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024 China

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First published: 05 April 2022
Citations: 18

Graphical Abstract

Enabled by de novo construction of the ether-linked hexopyranosyl units, the use of olefinic pyranoses as sugar precursors, and a gold(I)-catalyzed ring-closing glycosylation, the major starfish cyclic steroid glycosides, namely luzonicoside A and D and sepositoside A, have been synthesized for the first time.

Abstract

Starfishes have evolved with a special type of secondary metabolites, namely starfish saponins, to ward off various predators and parasites; among them, the starfish cyclic steroid glycosides stand out structurally, featuring a unique 16-membered ring formed by bridging the steroidal C3 and C6 with a trisaccharide. The rigid cyclic scaffold and the congested and vulnerable steroid-sugar etherate linkage present an unprecedented synthetic challenge. Here we report a collective total synthesis of the major starfish cyclic steroid glycosides, namely luzonicosides A (1) and D (2) and sepositoside A (3), with an innovative approach, which entails a de novo construction of the ether-linked hexopyranosyl units, use of olefinic pyranoses as sugar precursors, and a decisive ring-closing glycosylation under the mild gold(I)-catalyzed conditions.

Data Availability Statement

The data that support the findings of this study are available in the Supporting Information of this article.

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