Formal Enzymatic Reductive Amination with Ammonia

reductive amination - enzymes - transaminases - alcohol dehydrogenases

Significance

The authors report a biocatalytic reductive amination of ketones. The transformation is catalyzed by a combination of three different enzymes, a transaminase, an alanine dehydrogenase and a formate dehydrogenase. Under consumption of alanine to pyruvate, the products are formed with high yields and outstanding enantioselectivities. The recycling of alanine and the co-factor NAD(P)H is effected by ammonium ­formate in two independent enzymatic operations, producing water and CO₂ as only by-products.

Comment

Reductive amination is one of the most powerful and versatile methods for the ­preparation of amines from simple carbonyl ­compounds. The reported mild and efficient procedure shows the high potential of enzymes. Further investigations can give rise to more sophisticated and complex molecules involving biocatalysis. Beside several metal- and organocatalytic methods, this procedure represents a complementary and green approach towards ­nitrogen-containing molecules.