Chemoselective Henry Condensations Catalyzed by Artificial Carboligases

Abstract

The promiscuity of de novo designed enzymes provides a privileged platform for diverse abiological reactions. In this work, we report the first example of a nitroolefin synthase that catalyzes the Henry condensation between aromatic aldehydes and nitromethane. Significant catalytic activity was discovered in the computationally designed and evolved carboligase RA95.5-8, and mutations around the active site were shown to improve the reaction rate, demonstrating the potential to optimize the enzyme by directed evolution. This novel nitroolefin synthase could participate in complex biological cascades, whereby the highly tunable chemoselectivity could afford useful synthetic building blocks.

Engineered MOFs and Enzymes for the Synthesis of Active Pharmaceutical Ingredients

“…The subsequent dehydration of the nitro alcohol adduct to afford the β‐nitrostyrene product does not occurs at the oxyanion hole of the enzyme and generally requires high temperatures or strong basic conditions, as in the case of Cu@NiBDP (2‐butanol reflux, 48 h). However, the formation of the nitro alkene has been reported with the optimized RA95.5‐8 amino biocatalyst through the corresponding imine intermediate (see RA95.5‐8 in Figure ) . Manganese dependent hydroxynitrile lyase from Granulicella tundricula (GtHNL) have been also employed as promiscuous enzyme under similar reaction conditions to metal‐free HbHNL, but obtaining 75 % conversion of benzaldehyde after 24 h, with 94 % e.e.…”

“…However, the formation of the nitro alkene has been reported with the optimized RA95.5-8 amino biocatalyst through the corresponding imine intermediate (see RA95.5-8 in Figure 6). [36] Manganese dependent hydroxynitrile lyase from Granulicella tundricula (GtHNL) have been also employed as promiscuous enzyme under similar reaction conditions to metal-free HbHNL, but obtaining 75 % conversion of benzaldehyde after 24 h, with 94 % e.e. of the (R)-nitro alcohol enantiomer.…”

Tryptophan Synthase: Biocatalyst Extraordinaire

“…Nitroalkanes readily tautomerize to form a nucleophilic carbon alpha to the nitro group and have been used in the past as substrates for C-C bond formation reactions with electrophileactivating enzymes. [71][72][73] They have also been shown to react with chemically formed amino-acrylates to synthesize a wide range of amino acids, albeit under harsh conditions and with no enantioselectivity. [74][75][76][77] This led David Romney to hypothesize that nitroalkanes could act as nucleophiles in the TrpB βelimination reaction.…”

Enabling protein-hosted organocatalytic transformations

“…5d). 41 Enamine catalysis was also explored in the nitro-Michael addition of acetone to nitrostyrenes ( Fig. 5e).…”

“…[63][64][65][66][67][68] Nevertheless, it should be noted that, during the optimisation process, stereoselectivity may be weak because the active site undergoes reconstruction (e.g. relocating the catalytic residue); 40,41,44 eventually, stereoselectivity resumes and variants with kinetic parameters and selectivity similar to those of natural enzymes can be achieved. Furthermore, rened articial enzymes oen possess properties similar to those of natural enzymes.…”