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Chiral 1,2‐amino alcohols are widely represented in biologically active compounds from neurotransmitters to antivirals. While many synthetic methods have been developed for accessing amino alcohols, the direct aminohydroxylation of alkenes to unprotected, enantioenriched amino alcohols remains a challenge. Using directed evolution, we have engineered a hemoprotein biocatalyst based on a thermostable cytochromecthat directly transforms alkenes to amino alcohols with high enantioselectivity (up to 2500 TTN and 90 %ee) under anaerobic conditions withO‐pivaloylhydroxylamine as an aminating reagent. The reaction is proposed to proceed via a reactive iron‐nitrogen species generated in the enzyme active site, enabling tuning of the catalyst's activity and selectivity by protein engineering.

Chiral 1,2‐amino alcohols are widely represented in biologically active compounds from neurotransmitters to antivirals. While many synthetic methods have been developed for accessing amino alcohols, the direct aminohydroxylation of alkenes to unprotected, enantioenriched amino alcohols remains a challenge. Using directed evolution, we have engineered a hemoprotein biocatalyst based on a thermostable cytochromecthat directly transforms alkenes to amino alcohols with high enantioselectivity (up to 2500 TTN and 90 %ee) under anaerobic conditions withO‐pivaloylhydroxylamine as an aminating reagent. The reaction is proposed to proceed via a reactive iron‐nitrogen species generated in the enzyme active site, enabling tuning of the catalyst's activity and selectivity by protein engineering.

Sigmatropic rearrangements, while rare in biology, offer opportunities for the efficient and selective synthesis of complex chemical motifs. A “P411” serine‐ligated variant of cytochrome P450_BM3has been engineered to initiate a sulfimidation/[2,3]‐sigmatropic rearrangement sequence in whole E. coli cells, a non‐natural function for any enzyme, providing access to enantioenriched, protected allylic amines. Five mutations in the enzyme substantially enhance its activity toward this new function, demonstrating the evolvability of the catalyst toward challenging nitrene transfer reactions. The evolved catalyst additionally performs the highly enantioselective imidation of non‐allylic sulfides.

Sigmatropic rearrangements, while rare in biology, offer opportunities for the efficient and selective synthesis of complex chemical motifs. A “P411” serine‐ligated variant of cytochrome P450_BM3has been engineered to initiate a sulfimidation/[2,3]‐sigmatropic rearrangement sequence in whole E. coli cells, a non‐natural function for any enzyme, providing access to enantioenriched, protected allylic amines. Five mutations in the enzyme substantially enhance its activity toward this new function, demonstrating the evolvability of the catalyst toward challenging nitrene transfer reactions. The evolved catalyst additionally performs the highly enantioselective imidation of non‐allylic sulfides.