School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai, 200240, China.
Green Catalysis Center, and College of Chemistry, Zhengzhou University, Zhengzhou, 450001, China.
Angew Chem Int Ed Engl. 2023 Jan 9;62(2):e202214748. doi: 10.1002/anie.202214748. Epub 2022 Dec 2.
Chiral imidodiphosphates (IDPs) have emerged as strong Brønsted acid catalysts for many enantioselective processes. However, the dynamic transformation between O,O-syn and O,O-anti conformers typically results in low enantioselectivity. Here we demonstrate that topologies of metal-organic frameworks (MOFs) can be exploited to control IDP conformations and local chiral microenvironments for enantioselective catalysis. Two porous Dy-MOFs with different topologies are obtained from an enantiopure 1,1'-biphenol IDP-based tetracarboxylate ligand. While the ligand adopts a 4- or 3-connected (c) binding mode, all IDPs are rigidified to get only a single O,O-syn conformation and display greatly enhanced Brønsted acidity relative to the free IDP. The MOF with the 4-c IDP that has a relatively less compact shape than the 3-c IDP can be an efficient and recyclable heterogeneous Brønsted acid catalysing the challenging asymmetric O,O-acetalization reaction with up to 96 % enantiomeric excess.
手性亚膦酸二酯 (IDP) 已成为许多对映选择性过程的强布朗斯特酸催化剂。然而，O,O-顺式和 O,O-反式构象之间的动态转换通常导致低对映选择性。在这里，我们证明金属有机骨架 (MOF) 的拓扑结构可用于控制 IDP 构象和局部手性微环境以进行对映选择性催化。两种具有不同拓扑结构的多孔 Dy-MOF 是由手性纯 1,1'-联苯酚 IDP 衍生的四羧酸配体获得的。当配体采用 4-或 3-连接 (c) 结合模式时，所有 IDP 都被刚性化以仅获得单一的 O,O-顺式构象，并显示出比游离 IDP 更强的布朗斯特酸度。与 3-c IDP 相比，具有相对不那么紧凑形状的 4-c IDP 的 MOF 可以作为一种高效且可回收的非均相布朗斯特酸，用于具有挑战性的不对称 O,O-缩醛化反应，对映体过量高达 96%。
