Transfer Hydrogenations Catalyzed by Streptavidin-Hosted Secondary Amine Organocatalysts
Chem. Commun. 2021, 57, 1919-1922, 10.1039/d0cc08142f
Here, the streptavidin–biotin technology was applied to enable organocatalytic transfer hydrogenation. By introducing a biotin-tethered pyrrolidine (1) to the tetrameric streptavidin (T-Sav), the resulting hybrid catalyst was able to mediate hydride transfer from dihydro-benzylnicotinamide (BNAH) to α,β-unsaturated aldehydes. Hydrogenation of cinnamaldehyde and some of its aryl-substituted analogues was found to be nearly quantitative. Kinetic measurements revealed that the T-Sav:1 assembly possesses enzyme-like behavior, whereas isotope effect analysis, performed by QM/MM simulations, illustrated that the step of hydride transfer is at least partially rate-limiting. These results have proven the concept that T-Sav can be used to host secondary amine-catalyzed transfer hydrogenations.
Metal: ---Ligand type: Biotinylated pyrrolidineHost protein: Streptavidin (Sav)Anchoring strategy: SupramolecularOptimization: ---Reaction: Transfer hydrogenationMax TON: ---ee: ---PDB: 6GH7Notes: Maximum conversion is 95%; Efficiency of hydride transfer is largely affected by electrostatic properties of the para substituents of the aromatic a,b-unsaturated aldehyde substrate (cinnamaldehyde)