Structural studies on sulfonylbicyclo[n.2.0]alkan-1-ols

Abstract

The structures of a series of sulfonylbicyclo[n.2.0]alkan-1-ols (n = 3-6) 1-6 were determined by single-crystal x-ray diffraction. A survey of the Cambridge Structural Database and Monte Carlo conformational searches using MacroModel were performed. Compounds 1, 3 and 4 show intramolecular hydrogen bonding. Compound 2 is stabilized by three-centered bifurcated intra- and intermolecular hydrogen bonds between the hydroxyl proton and the sulfone oxygens. Compounds 5 and 6 are stabilized by intermolecular hydrogen bonds formed between the trans 1-hydroxy and sulfonyl moieties. In compounds 1-6, the degree of cyclotorsion of the four- five-, six-, seven- and eight-membered rings adjacent to the bond between the bridgehead atoms C1 and C4 is reflected in the magnitude about the exterior angles about C1 (C2 - C1 - Cx) and C4 (C3 - C4 - C5). The six-membered ring systems of 2, 5 and 6 showed noteworthy increases in the C5 - C4 - C1 - Cx and C3 - C4 - C1 - C2 torsion angles, and this was attributed to the conformational constraints of the pseudo-chair conformation of the six-membered ring. Similar conformational structure effects were observed in the modeled structures 1a-6a to those observed for the x-ray structures 1-6.