| Abstract: | The relationship between chiroptical properties of substituted bicyclic isoxazolidin‐5‐one derivatives and their molecular structures was investigated. The chromophoric system in isoxazolidinones was found to be nonplanar with a shallow pyramidal configuration at the N‐atom. The deviation from planarity can be attributed to the strain imposed by the bicyclic skeleton. Due to the nonplanarity, the isoxazolidinone system becomes inherently dissymmetric, which is supported by the high magnitude of the CD band occurring around 210 nm. In addition, the helicity of lactone moiety in investigated bicyclic isoxazolidinones is controlled by the absolute configuration at C(6). On this basis, a helicity rule correlating a positive (negative) helicity expressed by the O?C(8)? O(9)? N(1) torsional angle with a positive (negative) sign of the CD band around 210 nm was formulated. |
