Concise Synthesis of 1-Thioalkyl Glycoside Donors by Reaction of Per-O-acetylated Sugars with Sodium Alkanethiolates under Solvent-Free Conditions

Abstract

A relatively green method for synthesizing 1-thioalkyl glycosides has been developed, where sodium alkanethiolates were used to react with per-O-acetylated sugars instead of odorous alkyl mercaptans in the presence of BF3·Et2O without the use of solvents under mild conditions. Furthermore, we found that 1,2-trans-β-thioglycosides can be converted into corresponding 1,2-cis-α-thioglycosides in the presence of trifluoromethanesulfonic acid in nonpolar solvents under mild conditions. This provides a simple and efficient new approach for synthesizing challenging 1,2-cis-α-thioglycosides.

Efficient Preparation of 2‐SAc‐Glycosyl Donors and Investigation of Their Application in the Synthesis of 2‐Deoxyglycosides

“…It is well known that 1‐STol glycosides are highly active donors and are usually easily prepared from 1‐OAc sugars [14] . We then synthesized 1‐STol, 2‐SAc donors 53 , 54 , 55 and 56 from 29 , 31 , 34 and 36 , respectively (Figure 2).…”

“…It is well known that 1-STol glycosides are highly active donors and are usually easily prepared from 1-OAc sugars. [14] We then synthesized 1-STol, 2-SAc donors 53, 54, 55 and 56 from 29, 31, 34 and 36, respectively (Figure 2). The glycosylation of 53 with methyl 2,3,4-tri-OBz a-glucoside was first investigated (Table S1 in SI), and the disaccharide 57 with exclusive α-configuration was obtained in 82 % yield under optimized conditions.…”

A Robust Copper-Catalyzed Cross-Coupling of Glycosyl Thiosulfonate and Boronic Acids Enables the Construction of Thioglycosides

“…Typically, the preparation of thioglycosides can be achieved through two strategies: anomeric S-functionalization, which involves the formation of the S–aglycone bond, and S-glycosylation, which involves the formation of the glycosyl–S bond (Scheme C). S-Glycosylation is commonly performed via anionic reactions or radical coupling between glycosyl donors and thiols . Although some thiol surrogates have been elegantly designed by Wang, Walczak, , Jiang, and Feng, the indispensable use of less available and foul-smelling thiols in the synthesis restricts their wide application.…”

Solvent free, catalytic and diastereoselective preparation of aryl and alkyl thioglycosides as key components for oligosaccharide synthesis

“…Although the standard BF 3 •OEt 2 method 5,6 is dominant in the oligosaccharide synthesis literature, other approaches have also been published. These employ ZnCl 2 , 7 TfOH, 8 SnCl 4 , 9 and MoO 2 Cl 2 10 and are typically conducted in CH 2 Cl 2 and/or CH 3 CN.…”

“…CDCl 3 ) δ C 170.7, 170.2, 169.9 (CvO), 81.9 ( J C1,H1 167 6. Hz, C1), 71.8 (C2), 69.7 (C3), 69.0 (C5), 66.6 (C4), 62.7 (C6), 45.0 (SCH), 34.0 (CH 2 ), 33.6 (CH 2 ), 26.1 (CH 2 ), 26.0 (CH 2 ), 25.7 (CH 2 ), 21.1 (COCH 3 ), 20.8 (2× COCH 3 ), 20.8 (COCH 3 ).…”