ИСТИНА

Chiral α-amino acids (AA) with γ-tertiary and quaternary carbon centers display various biological activity. However, the design of the safe and simple methods for their production is still limited, underexplored and, from the point of the synthetic chemistry, is challenging task. Currently, the safe, promising and attractive protocol for the asymmetric synthesis of unnatural α-AAs becomes the addition of the generated in situ radicals to the alkene or imine derivatives based on chiral auxiliaries. We report about the efficient and practical protocol for the asymmetric synthesis of the unnatural α-amino acids with γ-tertiary and quaternary carbon centers via selective intermolecular iron-catalyzed olefin-olefin coupling of a chiral Ni(II) complex of dehydroalanine Schiff base ((S)-BPB-Ni-∆-Ala) with different olefins (Figure 1). Diastereomeric Ni(II) complexes with a ratio of up to dr >20:1 were isolated in 42–93% yields (18 examples). The target unnatural α-AAs were isolated with excellent enantioselectivity and yields up to 83%.