anti-Selective synthesis of β-boryl-α-amino acid derivatives by Cu-catalysed borylamination of α,β-unsaturated esters

A copper-catalysed regio- and diastereoselective borylamination of alpha,beta-unsaturated esters with B(2)pin(2) and hydroxylamines has been developed to deliver acyclic beta-boryl-alpha-amino acid derivatives with high anti-diastereoselectivity (up to >99 : 1), which is difficult to obtain by the established methods. A chiral phosphoramidite ligand also successfully induces the enantioselectivity, giving the optically active beta-borylated alpha-amino acids. The products can be stereospecifically transformed into beta-functionalised alpha-amino acids, which are of potent interest in medicinal chemistry.

Automated summary

A copper-catalyzed reaction has been developed for the regio- and diastereoselective borylamination of alpha,beta-unsaturated esters with B(2)pin(2) and hydroxylamines. The reaction delivers acyclic beta-boryl-alpha-amino acid derivatives with high anti-diastereoselectivity, which is difficult to achieve using established methods. Furthermore, the use of a chiral phosphoramidite ligand allows for the enantioselective synthesis of optically active beta-borylated alpha-amino acids. The resulting products can be further transformed into beta-functionalized alpha-amino acids, which are of great interest in medicinal chemistry.