Abstract
Here we report a practical, highly enantioselective photoredox allylation of aldehydes mediated by chiral nickel complexes with commercially available allyl acetate as the allylating agent. The methodology allows the clean stereoselective allylation of aldehydes in good to excellent yields and up to 93% e.e. using a catalytic amount of NiCl 2 (glyme) in the presence of the chiral aminoindanol-derived bis(oxazoline) as the chiral ligand. The photoredox system is constituted by the organic dye 3DPAFIPN and a Hantzsch's ester as the sacrificial reductant. The reaction proceeds under visible light irradiation (blue LEDs, 456 nm) at 8-12 °C with excellent stereoselectivities. Compared to other published procedures, no metal reductants (such as Zn or Mn), additives (e.g. CuI) or air-sensitive Ni(COD) 2 are necessary for this reaction. Accurate DFT calculations and photophysical experiments have clarified the mechanistic picture of this stereoselective allylation reaction showing a key role played by Hantzsch's ester for the turnover of the catalyst.
| Original language | English (US) |
|---|---|
| Journal | Angewandte Chemie (International ed. in English) |
| DOIs | |
| State | Published - Dec 22 2021 |
Bibliographical note
KAUST Repository Item: Exported on 2022-01-25Acknowledged KAUST grant number(s): URF/1/4025-01-01
Acknowledgements: P.G.C. acknowledges National project (PRIN 2017 ID: 20174SYJAF) SURSUMCAT “Raising up Catalysis for Innovative Developments” for financial support of this research. L.C. acknowledges King Abdullah University of Science and Technology (KAUST) for support within the CRG8 program, project the URF/1/4025-01-01, and the KAUST Supercomputing Laboratory for providing computational resources on the Shaheen II HPC infrastructure, and A.G., P.G.C. and P.C. acknowledge the University of Bologna for financial support.
ASJC Scopus subject areas
- General Chemistry
- Catalysis