Towards Enantiomerically Pure Unnatural α-Amino Acids via Photoredox Catalytic 1,4-Additions to a Chiral Dehydroalanine

-and diastereoselective 1,4-conjugate addi-tions of anionic and radical C-nucleophiles to a chiral bicyclic dehydroalanine (Dha) are described. Of particular importance, radical carbon photolysis by a catalytic photoredox process using a simple method with a metal-free photocatalyst provides exceptional yields and selectivities at room temperature. Moreover, these 1,4-conjugate additions offer an excellent starting point for synthesizing enantiomerically pure carbon-beta-substituted unnatural alpha-amino acids (UAAs), which could have a high potential for applications in chemical biology.

Automated summary

This research describes the diastereoselective 1,4-conjugate additions of anionic and radical C-nucleophiles to a chiral bicyclic dehydroalanine (Dha). Notably, radical carbon photolysis using a metal-free photocatalyst through a catalytic photoredox process provides exceptional yields and selectivities at room temperature. These 1,4-conjugate additions serve as an excellent starting point for synthesizing enantiomerically pure carbon-beta-substituted unnatural alpha-amino acids (UAAs), with potential applications in chemical biology.