Császár Zsófia, Guóth Mária, Kovács Margit, Bényei Attila C, Bakos József, Farkas Gergely
Research Group of Organic Chemistry-Synthesis and Catalysis, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary.
NMR Laboratory, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary.
Molecules. 2024 Aug 7;29(16):3743. doi: 10.3390/molecules29163743.
The development of new chiral ligands with simple and modular structure represents a challenging direction in the design of efficient homogeneous transition metal catalysts. Herein, we report on the asymmetric hydrogenation of prochiral ketones catalyzed by the iridium complexes of simple alkane-diyl-based P,N,O-type chiral ligands with a highly modular structure. The role of (i) the P-N and N-O backbone in the potentially tridentate ligands, (ii) the number, position and relative configuration of their stereogenic elements and (iii) the effect of their NH and OH subunits on the activity and enantioselectivity of the catalytic reactions are studied. The systematic variation in the ligand structure and the comparative catalytic experiments shed light on different mechanistic aspects of the iridium-catalyzed reaction. The catalysts containing the simple alkane-diyl-based ligands with central chirality provided high enantioselectivities (up to 98% ) under optimized reaction conditions and proved to be active and selective even at very high substrate concentrations (100 mmol substrate/mL solvent).
开发具有简单且模块化结构的新型手性配体是高效均相过渡金属催化剂设计中一个具有挑战性的方向。在此，我们报道了具有高度模块化结构的基于简单烷二基的P，N，O型手性配体的铱配合物催化前手性酮的不对称氢化反应。研究了（i）潜在三齿配体中P-N和N-O主链的作用，（ii）其立体化学元素的数量、位置和相对构型，以及（iii）它们的NH和OH亚基对催化反应活性和对映选择性的影响。配体结构的系统变化和比较催化实验揭示了铱催化反应的不同机理方面。含有具有中心手性的基于简单烷二基配体的催化剂在优化反应条件下提供了高对映选择性（高达98%），并且即使在非常高的底物浓度（100 mmol底物/ mL溶剂）下也证明具有活性和选择性。
