L. Noecker, J. A. Martino, P. Foley
Jan 30, 1998
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0
Influential Citations
11
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Journal
Tetrahedron-asymmetry
Abstract
Abstract Three methods for the synthesis of the deoxy sugar amicetose (2,3,6-trideoxy- d - erythro -hexopyranoside) are described. All three utilize the known dihydropyran 2-isobutoxy-6-methyl-2,3-dihydro-4 H -pyran as an intermediate. Asymmetric hydroboration of the dihydropyran with IpcBH 2 gave enantiomerically enriched isobutyl α and β-amicetosides. Hydroboration with borane–tetrahydrofuran followed by derivatization of the major product (β-anomer) with R -(−)-1-(1-naphthyl)ethylisocyanate gave diastereomeric carbamates which were separated and converted to isobutyl β- d and β- l -amicetosides having high optical purity. Racemic isobutyl β-amicetosides were also resolved by enzymatic transesterification using lipase and an acyl transfer reagent. Porcine pancreatic lipase and lipases from Candida rugosa and Pseudomonas sp. were evaluated in the presence of either vinyl acetate, vinyl butyrate, or trifluoroethyl butyrate as acylating agents. A GC-based method for determining enantiomeric purity of amicetose derivatives was developed.