Modular synthesis of congested β 2,2 -amino acids via the merger of photocatalysis and oxidative functionalisations.

A two-step protocol for the modular synthesis of β 2 - and α-quaternary β 2,2 -amino acid derivatives is reported. The key steps are a photocatalytic hydroalkylation reaction, followed by an oxidative functionalisation to access N -protected β-amino acids, esters, and amides. This strategy can be effectively scaled up via continuous-flow technology.