Synthesis of Thioglycosides by Tetrathiomolybdate‐Mediated Michael Additions of Masked Thiolates

Abstract

An efficient one-pot methodology for the synthesis of thioglycosides in excellent yields under neutral conditions through the use of benzyltriethylammonium tetrathiomolybdate [(BnNEt 3 ) 2 MoS 4 ; 1] as a sulfur-transfer reagent has been developed. The reagent 1 reacts with sugar halides to give sugar disulfides, which then undergo reductive cleavage in situ to provide the corresponding thiolates, followed by Michael addition to give the corresponding thioglycosides.

Chemistry of Polyvalent Iodine

“…The glucal derivative 290 was oxidized to the enone 291 by treatment with HTIB in acetonitrile (Scheme 97). 619…”

Synthesis of anomeric sulfonamides and their behaviour under radical-mediated bromination conditions

“…Several sulfonic acids and their salts attached to a sugar skeleton were described. The preparation of the required anomeric sulfinate 13 was effected by base-induced b-elimination from sulfon 11 which was obtained by oxidation of thioglucoside 5 22,23 by either Oxone Ò or mCPBA. Application of H 2 O 2 /Na 2 WO 4 20,21 to oxidize 5 gave sulfoxides 10…”

Masked Thiol Sugars: Chemical Behavior and Synthetic Applications of S‐Glycopyranosyl‐N‐monoalkyl Dithiocarbamates

“…[21] Other methodologies make use of glycosyl halides as starting material by their treatment with tetrathiomolybdate reagents. [22] The more challenging preparation of unsymmetrical nonreducing disaccharides that contain interglycosidic (1!1') disulfide linkages by the efficient coupling of two different oligosaccharide moieties versus the formation of the corresponding homodimers has been currently performed by means of the glycosulfenyl-transfer methodology using either glycosyl methanethiosulfonates [19] and S-glycosyl-N-acyl sulfenamides. [23] In addition, glycosyl thiols are at the base of a one-pot methodology that uses 1-chlorobenzotriazole as an in situ trapping/oxidizing agent [24] and also in a more elaborate three-step procedure in which sulfenic acids are generated from suitable sulfonyl intermediates.…”