Study Of Novel Glycosylations Based On The Glycal Donors And Synthesis Of Disaccharide Glycoside Of Angucycline Analogue

Glycals were an important class of organic intermediates in glycochemistry and could be used as key building blocks to synthesize biologically active compounds.In this thesis,the synthesis of 2-deoxyglycosides and 2,3-unsaturated glycosides were accomplished with glycals as starting materials and magnetic core-shell nanomaterial as catalyst.At the same time,our novel methodology was successfully applied to the synthesis of angucycline analog.My research was composed of three following parts:1.2-Deoxyoligosaccharides were key components in many biologically active natural products.In this part,synthetic approach to 2-deoxygalactosides was developed with peracetylated galactal as a raw material and Fe3O4@C@SO3H as a catalyst.This method had a wide range of substrates,including not only simple alcohols such as benzyl alcohol,n-octanol,propylene alcohol,but also complex alcohols such as menthol,cholesterol,and even sugar acceptors.At the same time,it also had the advantages of short reaction time(1-4 h),simple post-treatment,excellent yields(69-93%)and high stereoselectivity(?:? > 30:1).Moreover,one-pot synthesis of trisaccharides and the recycling of the catalyst could be realized,which made this methodology has a good application prospect in the synthesis of 2-deoxyglycosides.2.2,3-Unsaturated glycosides were a very important class of organic intermediates.In this part,a method for efficient preparing 2,3-unsaturated glycosides was developed with perbenzyl galactal as a raw material and Fe3O4@C@Al(III)as a catalyst.The method was applicable not only to structurally complex alcohol acceptors but also to glycoside donors of different protecting groups,and had high stereoselectivity,and the stereoselectivity of most products were ?:? > 19:1.At the same time,both the self-rearrangement and the addition side reactions could be effectively suppressed in this system.3.In this part,synthesis of a disaccharide glycoside analogs was carried out using 2,6-dideoxylated acylated glucose as raw material.In this research,the reaction intermediate was obtained by glycosylation,bromination and Diels-Alder reaction in sequence.Then,the intermediate was subjected to Ferrier rearrangement,following a series of reactions of deacylation,allylic hydroxyl oxidation,and Michael addition to obtain the desired disaccharide glycoside analog.In summary,the target compound was synthesized after 9 steps from 2,6-dideoxylated glucose acetate with total yield of 12.9%.