Syntheses of Enantiopure 1,2-Ethylenediamines with Tethered Secondary Amines of the Formula H2NCH2CH[(CH2) n NHMe]NH2 (n = 1–4) from α-Amino Acids: New Agents for Asymmetric Catalysis

Abstract

Tris(hydrochloride) adducts of the title compounds­ are prepared from the inexpensive α-amino acids H2N(C=O)CH2CH(NH2)CO2H, HO(C=O)(CH2) n′CH(NH2)CO2H (n′ = 1, 2), and H2N(CH2)4CH(NH2)CO2H, respectively (steps/overall yield = 5/32%, 7/30%, 7/33%, 5/38%). The NH2 group that is remote from the secondary amine is installed via BH3 reduction of an amide [–(C=O)NR2] derived­ from an α-amino carboxylic acid. The MeNHCH2 units are introduced by BH3 reductions of alkyl carbamate [RO(C=O)NHCH2–; R = Et, t-Bu] or amide [MeHN(C=O)–] moieties.