Hyperconjugative Interactions of the Carbon–Halogen Bond that Influence the Geometry of Cyclic α‑Haloacetals

The analysis of the structures of low-energy conformers of different α-haloacetals reveals changes in bond lengths and geometries that correspond to stabilizing orbital interactions that contribute to the ground-state structures of these systems. Several factors, including the electron-donating and electron-accepting abilities of the substituents on the ring, affect the degree of the electronic interactions in these carbohydrate-like systems. The presence of an α-halogen atom that can participate in hyperconjugation has been shown to contribute to the structural characteristics of the low-energy conformer. The experimental evidence is supported by natural bond order (NBO) analysis to identify the types of interactions and to assess their relative importance.对不同α-卤代半缩醛（α-haloacetals）的低能构象体结构开展分析，可揭示其键长与几何构型的变化特征，此类变化对应于稳定化轨道相互作用，而该相互作用是该类体系基态结构的重要贡献因素。环上取代基的给电子与吸电子能力等多重因素，会影响这类类碳水化合物体系中电子相互作用的强度。能够参与超共轭效应的α-卤原子的存在，已被证实会对低能构象体的结构特征产生显著影响。自然键轨道（Natural Bond Order，NBO）分析可为该实验证据提供支撑，用于识别相互作用类型并评估其相对重要性。