Department of Chemistry, Ludwig-Maximilians-University Munich, Butenandtstr. 5-13, 81377, Munich, Germany.
Max-Planck-Institute for Astronomy, Königstuhl 17, 69117, Heidelberg, Germany.
Angew Chem Int Ed Engl. 2019 May 6;58(19):6306-6310. doi: 10.1002/anie.201901175. Epub 2019 Mar 29.
The design of a new class of fluxional biphenyl bisphosphinite (BIBIPHOS) ligands decorated with amino acid-based diamide interaction sites is reported that undergo spontaneous desymmetrization. Hydrogenation of prochiral alkenes using Rh-BIBIPHOS results in enantiomeric ratios of up to 96:4 (R/S). This stereoconvergent behavior of the fluxional BIBIPHOS ligand is triggered by pronounced intermolecular interlocking of the recognition sites, leading to the formation of a supramolecular assembly, where the axial orientation of the biphenyl ligand backbone is governed by the chirality of the amino acid moieties. Stereoinduction during catalysis is decoupled from this process and occurs as an immediate consequence of the emergent behavior of the ligands. This supramolecular system is very robust and has the potential to be adopted for other ligand designs in enantioselective catalysis.
报道了一类新型的双膦亚胺（BIBIPHOS）配体的设计，这些配体具有基于氨基酸的二酰胺相互作用位点，能够自发地进行去对称化。使用 Rh-BIBIPHOS 氢化前手性烯烃，可得到高达 96:4（R/S）的对映体过量值。这种可极化 BIBIPHOS 配体的立体协同行为是由识别位点的显著分子间互锁触发的，导致形成超分子组装，其中联苯配体骨架的轴向取向受氨基酸部分的手性控制。催化过程中的立体诱导与该过程解耦，并作为配体的涌现行为的直接结果发生。这个超分子体系非常稳定，有可能被应用于手性催化中的其他配体设计。
