Pseudomonasfluorescenslipase (Amano) was found to be highly regioselective (85%) in the catalysed transesterification of 1,6-anhydro-β-D-glucopyranose using vinyl acetate as an acyl donor and solvent.
On the Regioselective Acylation of 1,6-Anhydro-β-<scp>d</scp>- and<scp>l</scp>-Hexopyranoses Catalysed by Lipases: Structural Basis and Synthetic Applications
With the aim of providing new methods for the regioselective protection at the 2, 3 and 4 positions of monosaccharides, we have studied the acetylation of a class of rigid sugars: the 1,6-anhydro-beta-D- and L-hexopyranoses (hexopyranosanes D-l to D-5 and L-1 to L-5), using vinyl acetate as an acyl donor and two common lipases,Candida rugosa and Pseudomonas cepacia, as catalysts. Our results indicate that the relative orientation of the hydroxyls governs the regioselectivity of acetylation. In the D-series, when the 3-OH is in the axial position, acetylation occurs mainly at the 4-axial OH, while the 2-axial OH is preferred when the 4-OH is equatorial. Conversely, when the 3-OH is equatorial, a strong selectivity affects the equatorial 2-OH. Compounds of the L-series were shown to be poor substrates for the lipase Pseudomonas cepacia except for L-galactosane for which the 2-monoacetyl ester was obtained in good yield. An attempt to rationalize the results by means of molecular modelling is also made to account for the catalytic activity of the Candida rugosa lipase on hexopyranosanes 1-3.
Zemek, Jiri; Kucar, Stefan; Anderle, Dusan, Collection of Czechoslovak Chemical Communications, 1987, vol. 52, # 9, p. 2347 - 2352
作者:Zemek, Jiri、Kucar, Stefan、Anderle, Dusan
DOI:——
日期:——
Some esters of levoglucosan
作者:David D. Ward、Fred Shafizadeh
DOI:10.1016/s0008-6215(00)81891-1
日期:1982.10
Schraml, Jan; Kucar, Stefan; Zeleny, Jan, Collection of Czechoslovak Chemical Communications, 1985, vol. 50, # 5, p. 1176 - 1183