Combination of Asymmetric Organo- and Biocatalytic Reactions in Organic Media Using Immobilized Catalysts in Different Compartments

A proof of concept for the combination of an asymmetric organocatalytic reaction with a biotransformation toward a “one-pot like” process for 1,3-diols based on immobilized organo- and biocatalysts, which are utilized in different compartments, is demonstrated. This process which runs completely in organic media consists of an initial proline-derivative-catalyzed aldol reaction and a subsequent reduction of the aldol adduct catalyzed by an alcohol dehydrogenase (ADH) without the need for intermediate isolation. Economically attractive superabsorber-based coimmobilization for the ADH and its cofactor NAD⁺ turned out to give a highly efficient biocatalyst with excellent reusability and simple product separation from the immobilizate under avoidance of any tedious extraction steps during the overall process

Chemoenzymatic Synthesis of Vitamin B5-Intermediate (<i>R</i>)‑Pantolactone via Combined Asymmetric Organo- and Biocatalysis

The combination of an asymmetric organocatalytic aldol reaction with a subsequent biotransformation toward a “one-pot-like” process for the synthesis of (<i>R</i>)-pantolactone, which to date is industrially produced by a resolution process, is demonstrated. This process consists of an initial aldol reaction catalyzed by readily available l-histidine followed by biotransformation of the aldol adduct by an alcohol dehydrogenase without the need for intermediate isolation. Employing the industrially attractive starting material isobutanal, a chemoenzymatic three-step process without intermediate purification is established allowing the synthesis of (<i>R</i>)-pantolactone in an overall yield of 55% (three steps) and high enantiomeric excess of 95%