Table 7. Proton relay mechanism, R=Ph

The ten year old Houk-List model, for rationalising the origin of stereoselectivity in the organocatalysed intermolecular aldol addition, is revisited using a variety of computational techniques which have been introduced or improved since the original study. Even for such a relatively small system, the role of dispersion interactions is shown to be crucial, along with the use of basis sets where the superposition errors are low. Understanding the non covalent interactions (NCI) at play is highlighted as essential for the design of new synthetic routes and alternative reactants. An NCI analysis of the transition states enables the identification of non-covalent interactions that determine the reaction outcome, confirming the role of the electrostatic NCHᵟ+∙∙∙Oᵟ- interactions and highlighting new geometric schemes based on dispersion. Alternative mechanisms, such as proton-relays involving a water molecule or the Hajos-Parrish alternative, are shown to be higher in energy. The Amsterdam manifesto, which espouses the principle that scientific data should be citable, is followed here by using interactive data tables assembled via calls to the data DOI (digital-object-identifiers) held on a digital repository.

本研究针对已有十年历史的霍克-利斯特模型（Houk-List model）展开重新审视——该模型用于阐释有机催化分子间羟醛加成反应中立体选择性的起源。研究采用了自原始研究问世以来新提出或优化的多种计算技术。即便针对此类相对小巧的体系，色散相互作用的作用亦被证实至关重要，同时需采用基组重叠误差较低的基组进行计算。明确反应中存在的非共价相互作用（NCI），是设计新型合成路径与替代反应物的核心前提。对反应过渡态开展NCI分析，可识别出决定反应结果的非共价相互作用：这一分析验证了静电性NCHδ+∙∙∙Oδ-相互作用的核心地位，并揭示了基于色散作用的新型几何作用模式。其他反应机理（例如涉及水分子的质子接力路径，或是哈乔斯-帕里希替代机理）均被证实具有更高的能垒。本研究遵循阿姆斯特丹宣言（Amsterdam manifesto）所倡导的"科学数据应可被引用"的原则，通过调用数字仓储中存储的、带有数字对象标识符（digital-object-identifiers，DOI）的数据，构建了交互式数据表。