Acta Cryst. (2007). E63, o4148  [ doi:10.1107/S1600536807045576 ]

rac-Diethyl [(1S,2R)-1-(4-bromophenyl)-6-hydroxy-3-oxo-2,3-dihydro-1H-benzo[f]chromen-2-yl]phosphonate

H. Krawczyk, L. Albrecht, J. Wojciechowski and W. M. Wolf

Abstract: In the title compound, C₂₃H₂₂BrO₆P, the -valerolactone ring adopts a distorted screw-boat conformation, with the diethoxyphosphoryl substituent occupying an axial position. An unusual eclipsed conformation is found for the P-C bond. The molecules form centrosymmetric dimers connected by O-HO hydrogen bonds. One of the methyl groups is disordered, with site occupancies of ca 0.8:0.2.

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