Redox reactions are involved in many essential industrial and biological processes. Nanoreactors have the potential to enable orchestrated redox reactions offering opportunities for energy storage and transformation of cheap and/or abundant starting materials into valuable products. We take redox-driven deracemizations as an archetypal redox approach to utilize poly(2-oxazoline)-based shell cross-linked micelles (SCMs) as nanoreactors to mimic biology’s metabolic systems regulating active oxidative and reductive sites in one single structure. Two catalysts, the organocatalyst TEMPO and the functionalized rhodium-based N-tosylated 1,2-diphenyl-1,2-ethylenediamine (Rh-TsDPEN), are spatially positioned into different domains of the SCMs. The catalyst site isolation enables otherwise non-orthogonal oxidative and reductive catalyses. The nitroxide mediated oxidation transfers racemic secondary alcohols into intermediate ketones, followed by the rhodium-catalyzed asymmetric transfer hydrogenation (ATH). Our compartmentalized bifunctional nanoreactors can convert a broad range of racemic secondary alcohols into synthetically valuable enantioenriched secondary alcohols with up to 97 % conversion and 98 % ee in aqueous media. Kinetic studies demonstrate that the SCMs can enhance the reactivity of both immobilized TEMPO and Rh-TsDPEN catalysts, compared to unsupported catalysts under the same reaction conditions.

Compartmentalized nanoreactors for one-pot redox-driven deracemizations

2019 Fall National Meeting

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