Scheme 13.

Enzymatic CO₂‐fixation cascades for the conversion of aromatic compounds into alcohols and amines. ^[43] (a) CO₂‐fixation cascades enabling the conversion of styrene into the corresponding allylic alcohol and amine. ^[43] (b) One‐pot three‐step enzymatic CO₂‐fixation cascade for the conversion of styrene into cinnamyl alcohol, involving a sequence of Fdc‐catalyzed carboxylation, CAR‐catalyzed carboxylate reduction, and carbonyl reduction catalyzed by endogenous alcohol dehydrogenase. ^[43] (c) One‐pot three‐step artificial CO₂‐fixation cascade involving a sequence of Fdc‐catalyzed carboxylation, CAR‐catalyzed carboxylate reduction and reductive aminase(RedAm)‐catalyzed reductive amination, enabling the conversion of styrene into the corresponding secondary amines; reaction contained (NH₄)HCO₃ as CO₂ source and cyclopropylamine as the primary amine source, and incorporated GDH‐based recycling of NADPH. ^[43] (d) One‐pot artificial CO₂‐fixation cascade enabling the conversion of styrene into the corresponding cinnamide involving AnFDC‐catalyzed carboxylation linked to CAR‐catalyzed amidation using NH₄HCO₃ as source of both CO₂ and NH₃. (e) CO₂‐fixation cascades enabling the conversion of benzofuran into the corresponding alcohol, amine, and amide featuring similar conditions to those for (b), (c), and (d) respectively but employing the engineered heteroaromatic (de)carboxylase AnFDC I327S as the carboxylation catalyst. ^[43] TpCAR=Tsukamurella paurometabola carboxylic acid reductase; SrCAR=Segniliparus rugosus carboxylic acid reductase; AnFdc=ferulic acid decarboxylase from Aspergillus niger; CfIRED=Cystobacter ferrugineus imine reductase; GDH=glucose dehydrogenase.