2-propynyl 2,3,4,6-tetra-O-acetyl - D-mannopyran-oside

Abstract

The 2-propynyl group in the title compound, C17H 22O10, adopts an exoanomeric conformation, with the acetyl-enic group gauche with respect to position C1. Comparison of 13C NMR chemical shifts from solution and the solid state suggest that the acetyl-enic group also adopts a conformation anti to C1 in solution. The pyran-ose ring adopts a 4 C1 conformation. Of the three secondary O-acetyl groups, that on position O4, flanked by two equatorial groups, adopts a syn conformation, in agreement with recent generalizations [González-Outeirĩo, Nasser & Anderson (2005). J. Org. Chem. 70, 2486-2493]. The acetyl group on position O3 adopts a gauche conformation, also in agreement with the recent generalizations, but that on position O2 adopts a syn conformation, not in agreement with the recent generalizations. © 2011 International Union of Crystallography.