Reaction of vinyl ethers with ArSCl adducts of d-glucal

Reduction of 2-Arylthio-β-C-D-Glucopyranosides with Different Functional Groups in the Lateral Chain

“…2-Arylthio-C-b-glycosides 1-7 (Table 1) were synthesized by the previously described method from tri-O-benzyl-D-glucal, ArSCl, and one of the following C-nucleophiles: 1-(trimethylsiloxy)cyclohexene, [6] methyl vinyl ether, [7] 1-methoxy-2-methyl-1-(trimethylsiloxy)propene, [6] 1-methoxy-2-methylpropene, [7] trimethylsilyl cyanide, [6] allyltrimethylsilane, [6] and 1-(trimethylsilyl)-1-(trimethylsiloxy)ethylene. [7] To obtain the desired 2-deoxy-b-C-glycosides, the 2-p-TolS group in compounds 1-7 had to be removed.…”

“…[7] To obtain the desired 2-deoxy-b-C-glycosides, the 2-p-TolS group in compounds 1-7 had to be removed. In this study, two distinct methods were used.…”

“…General Procedure for the Synthesis of 2-Arylthio-b-C-D-glucopyranosides 1-6 [6,7] A solution of 0.25 mmol of p-TolSCl in 0.3 mL of CH 2 Cl 2 was added dropwise to a solution of 0.25 mmol of tri-O-benzyl-D-glucal in 10 mL of CH 2 Cl 2 at room temperature. The color of the reaction mixture changed from yellow to colorless.…”

The synthesis of thiols, selenols, sulfides, selenides, sulfoxides, selenoxides, sulfones and selenones

“…Under Lewis acid conditions these adducts undergo reaction with vinyl ethers to give C-glycosides with excellent β-selectivity. 105 The anti-selectivity in the products suggests the reaction proceeds via a thiiranium ion intermediate. Interestingly, the product ratio is independent of the starting mixture suggesting that the α and β-thiiranium ion intermediates may be in equilibrium.…”

“…Interestingly, the product ratio is independent of the starting mixture suggesting that the α and β-thiiranium ion intermediates may be in equilibrium. 105 The formation of a thiiranium ion has recently been used to explain the stereochemical retention observed in the glycosylation of a thionucleoside under Mitsunobu conditions. 106 Similarly, Mitsunobu reaction of 4-thiofuranose derivative 32 gives a small amount of product which is believed to result from participation of the ring sulfur atom (Scheme 56).…”