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Functionalization of aromatic compounds by acylation has considerable significance in synthetic organic chemistry. As an alternative to chemical Friedel‐Crafts acylation, the C‐acyltransferase from Pseudomonas protegens has been found to catalyze C−C bond formation with non‐natural resorcinol substrates. Extending the scope of acyl donors, it is now shown that the enzyme is also able to catalyze C−S bond cleavage prior to C−C bond formation, thus aliphatic and aromatic thioesters can be used as acyl donors. It is worth to mention that this reaction can be performed in aqueous buffer. Identifying ethyl thioacetate as the most suitable acetyl donor, the products were obtained with up to >99 % conversion and up to 88 % isolated yield without using additional base additives; this represents a significant advancement to prior protocols. New tool available: As an alternative to chemical Friedel‐Crafts acylation, the C‐acyltransferase from Pseudomonas protegens catalyzes C−C bond [ABSTRACT FROM AUTHOR]

The Friedel-Crafts acylation is a broadly applied reaction that can be conducted using various types of catalyst. However, a biocatalytic alternative has only been reported recently. In this study, the scope of acetyl donors is described, showing that, in addition to vinyl acetate derivatives, phenyl esters are also suitable donors. Furthermore, it was found that various amines enhance the reaction, whereby the effect do not seem to be correlated to the pH but to the structure of the donor. For instance, 1,4-diazabicyclo[2.2.2]octane (DABCO) turned out to be a viable alternative to imidazole; however the former performed best at pH 9.85, whereas the latter performed best at pH 8.3. [ABSTRACT FROM AUTHOR]

The Friedel-Crafts acylation is commonly used for the synthesis of aryl ketones, and a biocatalytic version, which may benefit from the chemo- and regioselectivity of enzymes, has not yet been introduced. Described here is a bacterial acyltransferase which can catalyze Friedel-Crafts C-acylation of phenolic substrates in buffer without the need of CoA-activated reagents. Conversions reach up to >99 %, and various C- or O-acyl donors, such as DAPG or isopropenyl acetate, are accepted by this enzyme. Furthermore the enzyme enables a Fries rearrangement-like reaction of resorcinol derivatives. These findings open an avenue for the development of alternative and selective C−C bond formation methods. [ABSTRACT FROM AUTHOR]