Review on Recent Developments in Biocatalysts for Friedel–Crafts Reactions

Abstract

The Friedel−Crafts (F−C) reaction has been a fundamental pillar of both academic and industrial synthetic organic chemistry since its discovery in 1873. Its success is based on the versatility and applicability of F−C reactions for a wide range of substrates, and there have been an impressive number of publications and patents describing catalytic F−C reaction methods. The asymmetric version of the reaction was discovered about 100 years after the seminal work by Friedel and Crafts and has become a major area of research. While chemical methods with much-improved efficacies and scopes have been discovered, F−C reactions still suffer from limitations. Biocatalysis has the potential to be the best solution to this challenge because of the excellent selectivity (enantio-, chemo-, and regioselectivity) displayed by enzymes. In the last two decades, advancements in molecular biology techniques, bioinformatics, high-throughput screening, directed evolution, and process scale-up have led to biocatalysis becoming a mature field. It is therefore not surprising that researchers around the globe have developed several biocatalysts for asymmetric F−C reactions. Herein, we review recent developments in the design and use of catalytic and stereoselective strategies for performing the asymmetric F−C reactions.

Targeted development of sustainable green catalysts for regioselective acylation of aromatic ethers with carboxylic acidsviachlorosulfonic acid coated on poly(guanidine–triazine–sulfonamide) grafted quartz–γ-Fe2O3

“…1,2 In this respect, aromatic ketones extracted from these compounds are widely used as starting precursors to prepare chemicals with high values. 3 Typically, FC acylation is promoted by protic or Lewis acids that require a specific amount of catalyst regarding product inhibition. 4 Recently, several efforts have been made to enhance the FC reaction by developing high-performance catalysts.…”

“…4 Recently, several efforts have been made to enhance the FC reaction by developing high-performance catalysts. 3,5 In addition, catalysts (e.g., Nafion, zeolites, clays, graphene, metal oxides, and acids) and novel media (e.g., heterogeneous supports and ionic liquids) have been used for this purpose. [6][7][8][9][10][11][12][13][14] In FC acylation, it is possible to replace classical acyl chlorides with several activated carboxylic acid equivalents.…”

“…4 Recently, several efforts have been made to enhance the FC reaction by developing high-performance catalysts. 3,5 In addition, catalysts ( e.g. , Nafion, zeolites, clays, graphene, metal oxides, and acids) and novel media ( e.g.…”

Mutation of the eunicellane synthase Bnd4 alters its product profile and expands its prenylation ability

“…Finally, given our recent finding that bacterial diterpene synthases also catalyze the prenylation of small molecules using prenyl diphosphates that are shorter than their native substrates, 23 we saw an opportunity to assess the prenylation activity of Bnd4 variants to determine if we could expand their ability to perform Friedel-Crafts alkylation. 24,25 Bnd4 and…”

“…Finally, given our recent finding that bacterial diterpene synthases also catalyze the prenylation of small molecules using prenyl diphosphates that are shorter than their native substrates, 23 we saw an opportunity to assess the prenylation activity of Bnd4 variants to determine if we could expand their ability to perform Friedel–Crafts alkylation. 24,25 Bnd4 and other diterpene synthases such as CotB2 were shown to use both dimethylallyl diphosphate (DMAPP, C 5 ) and geranyl diphosphate (GPP, C 10 ) as prenyl donors but did not show prenylation activity with farnesyl diphosphate (FPP, C 15 ) or GGPP (C 20 ). 23 We proposed that the efficient production of GGOH ( 3 ) by Bnd4 Y197A provided an active site that may be more amenable to using longer prenyl donors for prenylation.…”