1
|
Bloomer BJ, Joyner IA, Garcia-Borràs M, Hu DB, Garçon M, Quest A, Ugarte Montero C, Yu IF, Clark DS, Hartwig JF. Enantio- and Diastereodivergent Cyclopropanation of Allenes by Directed Evolution of an Iridium-Containing Cytochrome. J Am Chem Soc 2024; 146:1819-1824. [PMID: 38190322 DOI: 10.1021/jacs.3c13011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2024]
Abstract
Alkylidene cyclopropanes (ACPs) are valuable synthetic intermediates because of their constrained structure and opportunities for further diversification. Although routes to ACPs are known, preparations of ACPs with control of both the configuration of the cyclopropyl (R vs S) group and the geometry of the alkene (E vs Z) are unknown. We describe enzymatic cyclopropanation of allenes with ethyl diazoacetate (EDA) catalyzed by an iridium-containing cytochrome (Ir(Me)-CYP119) that controls both stereochemical elements. Two mutants of Ir(Me)-CYP119 identified by 6-codon (6c, VILAFG) saturation mutagenesis catalyze the formation of (E)-ACPs with -93% to >99% ee and >99:1 E/Z ratio with just three rounds of 96 mutants. By four additional rounds of mutagenesis, an enzyme variant was identified that forms (Z)-ACPs with up to 94% ee and a 28:72 E/Z ratio. Computational studies show that the orientation of the carbene unit dictated by the mutated positions accounts for the stereoselectivity.
Collapse
Affiliation(s)
- Brandon J Bloomer
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Isaac A Joyner
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Marc Garcia-Borràs
- Institut de Química Computacional i Catàlisi (IQCC) and Departament de Química, Universitat de Girona, Girona 17003, Spain
| | - Derek B Hu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Martí Garçon
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| | - Andrew Quest
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Consuelo Ugarte Montero
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Isaac F Yu
- Department of Chemistry, University of California, Berkeley, California 94720, United States
| | - Douglas S Clark
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
- Department of Chemical and Biomolecular Engineering, University of California, Berkeley, California 94720, United States
| | - John F Hartwig
- Department of Chemistry, University of California, Berkeley, California 94720, United States
- Division of Chemical Sciences, Lawrence Berkeley National Laboratory, Berkeley, California 94720, United States
| |
Collapse
|