Three-Stage Conversion of Chemically Inert n-Heptane to α-Hydrazino Aldehyde Based on Bioelectrocatalytic C–H Bond Oxyfunctionalization

Abstract

Simple petrochemical feedstocks are often the starting material for the synthesis of complex commodity and fine and specialty chemicals. Designing synthetic pathways for these complex and specific molecular structures with sufficient chemo-, regio-, enantio-, and diastereo-selectivity can expand the existing petrochemicals landscape. The two overarching challenges in designing such pathways are selective activation of chemically inert C–H bonds in hydrocarbons and systematic functionalization to synthesize complex structures. Multienzyme cascades are becoming a growing means of overcoming the first challenge. However, extending multienzyme cascade designs is restricted by the arsenal of enzymes currently at our disposal and the compatibility between specific enzymes. Here, we couple a bioelectrocatalytic multienzyme cascade to organocatalysis, which are two distinctly different classes of catalysis, in a single system to address both challenges. Based on the development and utilization of an anthraquinone (AQ)-based redox polymer, the bioelectrocatalytic step achieves regioselective terminal C–H bond oxyfunctionalization of chemically inert n-heptane. A second biocatalytic step selectively oxidizes the resulting 1-heptanol to heptanal. The succeeding inherently simple and durable l-proline-based organocatalysis step is a complementary partner to the multienzyme steps to further functionalize heptanal to the corresponding α-hydrazino aldehyde. The “three-stage” streamlined design exerts much control over the chemical conversion, which renders the collective system a versatile and adaptable model for a broader substrate scope and more complex C–H functionalization.

Bioelectrocatalytic Synthesis: Concepts and Applications

“…Building upon their previous work, the Minteer group has shown the utility of enzymatic cascades by demonstrating an electroenzymatic-chemical cascade for the conversion of inert heptane to α-hydrazino aldehydes. [104] NADH regeneration is circumvented by an anthraquinone (AQ) modified LPEI to mediate electron transfer to the rubredoxin (alkG). Initiated by MET, alkG transferred electrons to alkane monooxygenase (alkB), which yielded terminal alcohols on the heptane, and the resulting heptanol was converted to the aldehyde by a choline oxidase (AcCO 6 ).…”

“…Building upon their previous work, the Minteer group has shown the utility of enzymatic cascades by demonstrating an electroenzymatic‐chemical cascade for the conversion of inert heptane to α‐hydrazino aldehydes [104] . NADH regeneration is circumvented by an anthraquinone (AQ) modified LPEI to mediate electron transfer to the rubredoxin (alkG).…”

Isobaric Vapor–Liquid Equilibrium of Ethyl Acetate + 1-Hexanol, Methanol + 1-Hexanol, and n-Heptane + Cyclohexanol Binary System at 101.3 kPa

“…A separation technique used in the chemical industry called extractive distillation has as its primary goals the purification of raw materials, the separation of azeotropic mixtures, cost savings, and the reduction of pollutant emissions in order to meet production demands. , Separation operations are essential in the production of the chemical, pharmaceutical, and petrochemical sectors and are the most significant factor in determining the quality and efficacy of the production. Ethyl acetate and methanol/ n -heptane are important raw materials widely used in chemical production. − In order to reduce resource consumption in the production process, obtain high-purity products, and reduce environmental pollution caused by waste liquid discharge, it is extremely necessary to separate the ethyl acetate + methanol , and ethyl acetate + n -heptane azeotropic systems.…”