| Title: |
Modular enantioselective photocatalysts from privileged pybox scaffolds. |
| Authors: |
Kelch, Riley M.; Hämmerling, Lea; Zysman-Colman, Eli; Yoon, Tehshik P. |
| Source: |
Science; 4/9/2026, Vol. 392 Issue 6794, p188-193, 6p |
| Subject Terms: |
Photocatalysts; Asymmetric synthesis; Chromophores; Photoinduced electron transfer; Ligands (Chemistry) |
| Abstract: |
Modern organic synthesis relies upon the availability of chiral catalysts to control the stereochemistry of bond-forming reactions. Several families of chiral catalysts have become recognized as "privileged" structures because of their notable generality for diverse transformations with different reaction mechanisms. However, examples of highly enantioselective photocatalyst structures remain scarce. We have designed a family of enantioselective photocatalysts by modifying the structures of privileged pyridine bis(oxazoline) complexes with electron-donating carbazole units. The chiral ligands are accessible through a three-step synthetic sequence starting from commercially available chiral pool materials, and their charge-transfer photochemistry can be rationally tuned to optimize photocatalytic activity. We demonstrate the generality of these new chiral photocatalyst structures in a series of three model asymmetric reactions, which includes both photoredox and excited-state photoreactions. Editor's summary: It is essential when manufacturing pharmaceuticals to distinguish the effects of mirror image molecular structures called enantiomers. Chemists have therefore thoroughly optimized catalysts that can favor production of a single enantiomer in a wide range of thermal reactions. By contrast, asymmetric photocatalysis has lagged behind, in part because the source of asymmetry is often distinct from the light-absorbing chromophore. Kelch et al. now report a versatile class of catalysts that combine a well-established chiral pyridine bis(oxazoline) ligand with a carbazole chromophore in a single structure and showcase its applicability to multiple photochemical reactions. —Jake S. Yeston [ABSTRACT FROM AUTHOR] |
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| Database: |
Complementary Index |