A general synthesis of unnatural α-amino acids by iron-catalysed olefin–olefin coupling via generated radicals

摘要: Herein, we report an efficient and practical protocol for the asymmetric synthesis of unnatural α-amino acids (AAs) with γ-tertiary quaternary carbon centres via selective intermolecular iron-catalysed olefin–olefin coupling a chiral Ni(II) complex dehydroalanine Schiff base 2 ((S)-BPB-Ni-Δ-Ala) different olefins. In all successful reactions, diastereomeric nickel complexes were typically obtained in ratio up to dr > 20 : 1. The desired products isolated 42–93% yields (18 examples). Exemplarily, three decomposed aqueous HCl target excellent enantioselectivities 83%. auxiliary (BPB = 2-(N-benzylprolyl)aminobenzophenone) was readily recycled reused starting 2. developed provided facile access analogues glutamic acid, leucine phosphinothricin.