Design and synthesis of hydrophobic, bulky χ2-constrained phenylalanine and naphthylalanine derivatives

A series of novel hydrophobic, bulky χ2-constrained phenylalanine and naphthylalanine derivatives were designed and synthesized. Asymmetric hydrogenations of α-enamides using Burkʹs DuPHOS-based Rh(I) catalysts generated high enantiomerically pure α-amino acid derivatives, which subsequently underwent Suzuki cross couplings with boronic acid derivatives to afford these aromatic substituted amino acids in high yields and with high enantioselectivity.