Photoenzymatic Synthesis of -Tertiary Amines By Engineered Flavin-Dependent ‘Ene’-Reductases

𝛼-tertiary amines are a common motif in pharmaceutically important molecules but are challenging to prepare using asymmetric catalysis. Here, we demonstrate engineered flavin-dependent ‘ene’-reductases (EREDs) can catalyze radical additions into oximes to prepare this motif. Two different EREDs were evolved into competent catalysts for this transformation with high levels of stereoselectivity. Mechanistic studies indicate that the oxime contributes to the enzyme templated CT-complex formed between the substrate and cofactor. These products can be further deri-vatized to prepare a variety of motifs, highlighting the ver-satility of ERED photoenzymatic catalysis for organic syn-thesis.