Back to Search
Start Over
A light-driven enzymatic enantioselective radical acylation.
- Source :
-
Nature [Nature] 2024 Jan; Vol. 625 (7993), pp. 74-78. Date of Electronic Publication: 2023 Dec 18. - Publication Year :
- 2024
-
Abstract
- Enzymes are recognized as exceptional catalysts for achieving high stereoselectivities <superscript>1-3</superscript> , but their ability to control the reactivity and stereoinduction of free radicals lags behind that of chemical catalysts <superscript>4</superscript> . Thiamine diphosphate (ThDP)-dependent enzymes <superscript>5</superscript> are well-characterized systems that inspired the development of N-heterocyclic carbenes (NHCs) <superscript>6-8</superscript> but have not yet been proved viable in asymmetric radical transformations. There is a lack of a biocompatible and general radical-generation mechanism, as nature prefers to avoid radicals that may be harmful to biological systems <superscript>9</superscript> . Here we repurpose a ThDP-dependent lyase as a stereoselective radical acyl transferase (RAT) through protein engineering and combination with organophotoredox catalysis <superscript>10</superscript> . Enzyme-bound ThDP-derived ketyl radicals are selectively generated through single-electron oxidation by a photoexcited organic dye and then cross-coupled with prochiral alkyl radicals with high enantioselectivity. Diverse chiral ketones are prepared from aldehydes and redox-active esters (35 examples, up to 97% enantiomeric excess (e.e.)) by this method. Mechanistic studies reveal that this previously elusive dual-enzyme catalysis/photocatalysis directs radicals with the unique ThDP cofactor and evolvable active site. This work not only expands the repertoire of biocatalysis but also provides a unique strategy for controlling radicals with enzymes, complementing existing chemical tools.<br /> (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)
- Subjects :
- Acylation
Aldehydes metabolism
Catalytic Domain
Free Radicals metabolism
Ketones metabolism
Oxidation-Reduction
Protein Engineering
Stereoisomerism
Thiamine Pyrophosphate metabolism
Acyltransferases chemistry
Acyltransferases metabolism
Biocatalysis radiation effects
Light
Lyases chemistry
Lyases metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1476-4687
- Volume :
- 625
- Issue :
- 7993
- Database :
- MEDLINE
- Journal :
- Nature
- Publication Type :
- Academic Journal
- Accession number :
- 38110574
- Full Text :
- https://doi.org/10.1038/s41586-023-06822-x