title: Highly Stereoselective Biocatalytic Synthesis of Key Cyclopropane Intermediate to Ticagrelor.
abstract: Extending the scope of biocatalysis to important non-natural reactions such as olefin cyclopropanation will open new opportunities for replacing multi-step chemical syntheses of pharmaceutical intermediates with efficient, clean, and highly selective enzyme-catalyzed processes. In this work, we engineered the truncated globin ofBacillus subtilisfor the synthesis of a cyclopropane precursor to the antithrombotic agent ticagrelor. The engineered enzyme catalyzes the cyclopropanation of 3,4-difluorostyrene with ethyl diazoacetate on a preparative scale to give ethyl-(1R, 2R)-2-(3,4-difluorophenyl)-cyclopropanecarboxylate in 79% yield, with very high diastereoselectivity (>99% dr) and enantioselectivity (98%ee), enabling a single-step biocatalytic route to this pharmaceutical intermediate.
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, United States.
authors.forename: Kari E
authors.initials: KE
authors.lastname: Hernandez
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, United States.
authors.forename: Hans
authors.initials: H
authors.lastname: Renata
authors.affiliation: Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, United States.
authors.forename: Russell D
authors.initials: RD
authors.lastname: Lewis
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, United States.
authors.forename: S B
authors.initials: SB
authors.lastname: Jennifer Kan
authors.affiliation: Provivi, Inc., Santa Monica, CA, 90404, United States.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Provivi, Inc., Santa Monica, CA, 90404, United States.
authors.forename: Jared
authors.initials: J
authors.lastname: Forte
authors.affiliation: Provivi, Inc., Santa Monica, CA, 90404, United States.
authors.forename: David
authors.initials: D
authors.lastname: Rozzell
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, United States.
authors.forename: John A
authors.initials: JA
authors.lastname: McIntosh
authors.affiliation: Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA, 91125, United States; Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, 91125, United States.
authors.forename: Frances H
authors.initials: FH
authors.lastname: Arnold
keywords: Bacillus subtilis; biocatalysis; cyclopropanation; directed evolution; ticagrelor; truncated globin