2-C-Cyclohexyl-2,3-O-isopropylideneerythrofuranose

In the title compound, C13H22O4, the acetonide ring adopts an envelope conformation with one of the O atoms as the flap atom, whereas a twisted conformation is found for the furanose ring. Centrosymmetric eight-membered {⋯OCOH}2 synthons involving the hydroxy H and acetonide O atoms are found in the crystal structure. These are linked into a supramolecular chain in the a-axis direction via C—H⋯O contacts.

In the title compound, C 13 H 22 O 4 , the acetonide ring adopts an envelope conformation with one of the O atoms as the flap atom, whereas a twisted conformation is found for the furanose ring. Centrosymmetric eight-membered {Á Á ÁOCOH} 2 synthons involving the hydroxy H and acetonide O atoms are found in the crystal structure. These are linked into a supramolecular chain in the a-axis direction via C-HÁ Á ÁO contacts.

Comment
Recently we examined the dihydroxylation of the olefin portion of 1,2-dioxines, which provided access to a range of polyhydroxylated core structures upon selective manipulation of the peroxide linkage (Robinson et al., 2006;Robinson et al., 2009;Valente et al., 2009). This methodology was extended to include the synthesis of erythrono-γ-lactones (Pedersen et al., 2009), during the course of which the title compound, (I), was prepared.
The molecular structure of (I), Fig. 1, comprises two fused five-membered rings linked by the C2-C3 bond. The acetonide ring adopts an envelope conformation with the O2 atom being the flap atom. A twisted conformation is found for the furanose ring whereby the O3 atom is endo and the C4 atom is exo. The cyclohexyl group is in the chair conformation. The crystal structure comprises centrosymmetric dimers held by {···OCOH} 2 synthons arising from the interaction between the O4-hydroxyl group and the ether-O3 atom, Fig. 2 and Table 1. The resultant eight-membered ring has an elongated chair conformation. The dimeric aggregates are linked into supramolecular chains via C-H···O interactions, Fig. 2 and Table 1.
The topology of the supramolecular chain is linear, and is aligned along the a direction.

Refinement
Carbon-bound H-atoms were placed in calculated positions (C-H 0.98-1.00 Å) and were included in the refinement in the riding model approximation with U iso (H) set to 1.2-1.5U eq (C). A rotating group model was used for the methyl groups.