Sodium borohydride reduction of E-3-benzylidenechromanone epoxides in dry methanol has afforded 3(S*), 4(S*)-dihydroxy-3-alpha(R*)-methoxybenzylchromans as an interesting class of products, the structures of which have been assigned mainly from spectral data and consideration of the mechanistic aspects. X-ray diffraction study of one of them, 3-4-bromo-alpha(R*)-methoxybenzyl-6-chloro-3(S*),4(S*)-dihydroxychroman, is performed. The title compound crystallizes in the monoclinic sp. gr. P2(1)/n, with a = 13.336(6) A,b = 10.866(5) A, c = 27.166(11) A, beta = 95.193(6)degrees, V = 3920(3) A(3), and Z = 8. Supramolecular construction of the compound involves OHO intermolecular hydrogen bonds as well as three other types of non-covalent interactions which are responsible for crystal packing. Density functional theory was applied for geometry optimization, molecular orbital calculations, and prediction of UV spectral features. The geometric parameters (bond lengths, bond angles, and dihedral angles) for the representative compound obtained from density functional theory with B3LY6-31G basis set were in good agreement with experimental values.
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