Synthesis of Isoxazolin-5-one Glucosides by a Cascade Reaction.

The Journal of organic chemistry

PubMedID: 24266449

Becker T, Görls H, Pauls G, Wedekind R, Kai M, von Reuß SH, Boland W. Synthesis of Isoxazolin-5-one Glucosides by a Cascade Reaction. J Org Chem. 2013;.
A novel synthetic route was developed for the construction of isoxazolin-5-one glucosides using a cascade reaction. The reaction involves a nucleophilic attack of the 5´-OH group on the 1´-carbon of the oxime moiety (6-exo-trig reaction) to alpha/beta-ii followed by a second nucleophilic attack of the nitrogen atom on the beta-position of the propynoyl moiety (5-endo-dig reaction). An X-ray crystal structure of the isoxazolin-5-one glucoside 6 confirmed the structure and stereochemistry of the heterocycle. Using immobilized Candida antarctica Lipase B the synthesis of 2-[6'-(3"-nitropropanoyl)-beta-D-glucopyranosyl]-3-isoxazolin-5-one, a natural toxin from plants and insects was achieved by enzymatic transesterification without additional protective groups.