Stereoselective Friedel–Crafts alkylation catalyzed by squalene hopene cyclases

In organic synthesis the Friedel–Crafts alkylation is of eminent importance, as it is a key reaction in many synthetic routes. A general access to enzymatic Friedel–Crafts alkylations would be very beneficial due to the high selectivity of biocatalysts. We used designed polyprenyl phenyl ethers to specifically address this reaction by using squalene hopene cyclases as catalysts. Polycyclic products with aromatic rings constituting important biological active compounds were obtained. Our results demonstrate that squalene hopene cyclases can be utilized for Friedel–Crafts alkylations and reveal the potential of these enzymes for chiral Brønsted acid catalysis.