Asymmetric biomimetic aldol reaction of glycinate enables highly efficient synthesis of chiral β-hydroxy-α-amino acid derivatives

Abstract

Efficient biomimetic reactions provide a powerful platform for producing bioactive chiral compounds. Chiral β-hydroxy-α-amino acids display exceptionally high bioactivity and are key functional components of many marketed drugs. However, the efficient synthesis of chiral β-hydroxy-α-amino acids remains a long-standing challenge for both chemical and biological syntheses. Chemical synthesis is problematic due to low step- and atom-efficiencies, high costs and environmental hazards. The enzymatic aldol reaction of glycine can make β-hydroxy-α-amino acids in one step, but it is constrained by issues such as limited substrate scope, unsatisfactory stereoselectivity and low conversion. Here we have successfully realized the biomimetic aldol reaction of glycinate with aldehydes, using 0.01–1.0 mol% of a chiral pyridoxal as the catalyst to produce a remarkably broad range of chiral β-hydroxy-α-amino esters. Moreover, a high-diversity parallel asymmetric synthesis has also been tested using over 1,100 aldehydes and it yielded over 1,700 chiral β-hydroxy-α-amino acid esters, demonstrating its important potential for drug innovation.