Total Synthesis of Starfish Cyclic Steroid Glycosides.Part 1,Synthesis of the Aglycone and Attempts at Installation of the Sugar Units  

作　　者：Bingfeng Shi Youxi Chen Mingyu Geng Dapeng Zhu Biao Yu 

机构地区：[1]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 [2]Department of Chemistry,Zhejiang University,Hangzhou,Zhejiang,310027 China

出　　处：《Chinese Journal of Chemistry》2023年第8期891-896,共6页中国化学（英文版）

基　　金：the financial support from the National Natural Science Foundation of China(21901251);Shanghai Sailing Program(19YF1458400);Laboratory for Marine Drugs and Bioproducts of Qingdao National Laboratory for Marine Science and Technology(LMDBKF201803).

摘　　要：Comprehensive Summary Sepositoside A(1)is the major and first cyclic steroid glycoside isolated from starfishes,which features a strained 16-membered ring formed by tethering C3 and C6 of the steroid aglycone with a linear trisaccharide.We conceived a convergent synthetic plan in which sepositoside A was disconnected into a disaccharide and a steroid-glucose hybrid ether.The desired 3β,6β-dihydroxy-Δ7,8-23-one aglcyone was readily prepared from dehydroepiandrosterone in 12 steps.The etherification of the 6β-hydroxy-Δ7,8-steroid with a variety of hexopyranoside-C6-electrophiles and CO_(2)-extrusion of a steroid-pyranose hybrid carbonate were extensively studied;however,formation of the desired steroid-pyranose etherate linkage has not been successful.Model studies on theβ-selective installation of the(1→2)-linked disaccharide onto the steroidal C3β-OH with the corresponding disaccharideα-imidates were also examined,however,formation of theα-glycosides prevailed.The present results force us to explore alternative approaches to construct the steroid-pyranose etherate linkage and stepwise assembly of the glycans en route to the starfish cyclic steroid glycosides,which will be presented in two articles that follow.

关 键 词：Cyclic starfish glycosides ETHERIFICATION Glycosylation STEROID Total synthesis 

分 类 号：O62[理学—有机化学]