Directed Evolution Enables Dynamic Control of Transient Intermediates for Anti-Markovnikov Wacker-Tsuji-Type Oxidation of Unactivated Alkenes

17 September 2024, Version 2

Abstract

Controlling the dynamic behavior of highly reactive fleeting intermediates is an intriguing concept to generate selectivity in competing reaction pathways. Here we report the directed evolution of a P450 enzyme for anti-Markovnikov-selective Wacker-Tsuji-type oxidation of unactivated alkenes. This reaction is a long-standing challenge in catalysis due to its unfavorable energetics and competing reactions. The evolved aMOx-A enzyme performs anti-Markovnikov oxidation of unactivated alkenes with several hundred turnovers and possesses kinetic parameters comparable to those of average natural enzymes. The biocatalyst guides an oxo-transfer process through multiple competing reactions, including bifurcating reaction pathways that originate after a rate-limiting transition state. Chemoselectivity of aMOx-A arises from controlling substrate conformations as well as dynamics of reactive intermediates. This includes accessing and controlling a fleeting carbocation intermediate that does not correspond to a minimum on the potential energy surface. Engineering of aMOx-A highlights how directed enzyme evolution optimizes unique catalytic processes that have largely eluded efficient catalysis.

Keywords

Directed evolution
Biocatalysis
P450
carbocation
bifurcations
oxidation
anti-Markovnikov
alkenes

Supplementary materials

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Description
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Title
Supplementary information
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Materials and Methods, General procedures, Supporting Figures, Supporting Tables, NMR spectra
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