Multienzymatic Processes Involving Baeyer–Villiger Monooxygenases

Baeyer–Villiger monooxygenases (BVMOs) are flavin-dependent oxidative enzymes capable of catalyzing the insertion of an oxygen atom between a carbonylic Csp2 and the Csp3 at the alpha position, therefore transforming linear and cyclic ketones into esters and lactones. These enzymes are dependent on nicotinamides (NAD(P)H) for the flavin reduction and subsequent reaction with molecular oxygen. BVMOs can be included in cascade reactions, coupled to other redox enzymes, such as alcohol dehydrogenases (ADHs) or ene-reductases (EREDs), so that the direct conversion of alcohols or α,β-unsaturated carbonylic compounds to the corresponding esters can be achieved. In the present review, the different synthetic methodologies that have been performed by employing multienzymatic strategies with BVMOs combining whole cells or isolated enzymes, through sequential or parallel methods, are described, with the aim of highlighting the advantages of performing multienzymatic systems, and show the recent advances for overcoming the drawbacks of using BVMOs in these techniques.

Direct Conversion of Alcohols to Long-Chain Hydrocarbons via Tandem Dehydrogenation-Decarbonylative Olefination

<p>Design of active and selective supported catalysts is critical for developing new tandem processes for upgrading biomass-derived alcohols. Hydrogen-free upgrading alcohols to liquid hydrocarbons is desirable for producing drop-in fuel substitutes, but direct and atom-economical processes are yet to be reported. Here we report a novel alcohol upgrading and<b> </b>deoxygenation cascade that meets these criteria. This hydrogen-free cascade is catalyzed by multifunctional Pd catalysts, whose supports feature a range of acid-base properties: primarily basic MgO, acidic Al₂O₃ and Mg-Al hydrotalcite (HT) with a combination of Lewis acidic and basic sites. The impact of support selection on selectivity offers insights into the design principles for next-generation catalysts for this process and related transformations.</p>

Direct Conversion of Alcohols to Long-Chain Hydrocarbons via Tandem Dehydrogenation-Decarbonylative Olefination

<p>Design of active and selective supported catalysts is critical for developing new tandem processes for upgrading biomass-derived alcohols. Hydrogen-free upgrading alcohols to liquid hydrocarbons is desirable for producing drop-in fuel substitutes, but direct and atom-economical processes are yet to be reported. Here we report a novel alcohol upgrading and<b> </b>deoxygenation cascade that meets these criteria. This hydrogen-free cascade is catalyzed by multifunctional Pd catalysts, whose supports feature a range of acid-base properties: primarily basic MgO, acidic Al₂O₃ and Mg-Al hydrotalcite (HT) with a combination of Lewis acidic and basic sites. The impact of support selection on selectivity offers insights into the design principles for next-generation catalysts for this process and related transformations.</p>