π-Facial selectivities of diastereotopic ketones: p-bromobenzoates of 4-hetero-1-decalinols

Abstract

The crystal structures of the p-bromobenzoates of cis-4-oxa-1-decalinyl (C₁₆H₁₉BrO₃), trans-4-oxa-1-decalinyl (C₁₆H₁₉BrO₃), N-benzyl-cis-4-aza-1-decalinyl (C₂₃H₂₆BrNO₂), N-benzyl-trans-4-aza-1-decalinyl (C₂₃H₂₆BrNO₂) and trans-4-thia-1-decalinyl (C₁₆H₁₉BrO₂S) (decalin is perhydronaphthalene) have been determined as part of a study directed at predicting and interpreting the -facial selectivities of diastereotopic ketones in reactions with nucleophiles. All five structures are composed of molecules that are separated by normal van der Waals distances. In all five structures, the heterocyclic and cyclohexyl rings adopt chair conformations, and the p-bromobenzoate groups are planar.