Syntheses of glycosyl phosphates by phase transfer catalysis

Abstract

R E N~ ROY, FRANGOIS D. TROPPER, and CHANTAL GRAND-MAITRE. Can. J. Chem. 69, 1462Chem. 69, (1991. The peracetylated glycosyl bromides of D-glucose (I), D-galactose (2), and D-lactose (5) were treated with dibenzyl phosphate in a catalytic two-phase system using tetrabutylammonium hydrogen sulfate as catalyst. The reactions proceeded by complete inversion at the anomeric centers and afforded a new stereospecific entry into 1 ,2-trans-P-D-glycosyl phosphates of peracetylated D-glucose (3), D-galactose (4), and the disaccharide D-lactose (6) in 83, 73, and 83% yields respectively. Interestingly, the glycosyl chloride 7 furnished the oxazoline 9 rather than the expected glycosyl phosphate 8.

1,2-Amino Alcohols and Their Heterocyclic Derivatives as Chiral Auxiliaries in Asymmetric Synthesis

“…Reaction of an allyl alcohol with trichloroacetonitrile provides a useful method for the preparation of amino alcohols that has been exploited in the synthesis of amino sugars; the reaction proceeds through an oxazoline 24 (Scheme ). −

22

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The type 2 intramolecular imino Diels-Alder reaction. Synthesis and structural characterization of bicyclo[n.3.1] bridgehead olefin/bridgehead lactams

“…6-(Tetrahydropyranyloxy)-1 -iodohexane (16). A solution of alcohol 15 (18.4 g, 91.0 mmol) and triethylamine (9.8 g, 96.9 mmol, 1.06 equiv) in CH2C12 (400 mL) cooled to 0 °C was treated with methanesulfonyl chloride (11.1 g, 96.9 mmol, 1.06 equiv).…”

A Preparative Synthesis of Human Chitinase Fluorogenic Substrate (4′‐Deoxychitobiosyl)‐4‐methylumbelliferone

“…Introduction of the umbelliferyl chromophore was accomplished by S N 2 displacement of the anomeric α-chloride by the tetrabutylammonium salt of 4-methylumbelliferone, generated under phase-transfer conditions. [32] The protected umbelliferyl derivative was obtained in 62 % yield as a white …”