title: Preparation of diamines by lithiation-substitution of imidazolidines and pyrimidines.
abstract: The synthesis of chiral 1,2-diamines and 1,3-diamines was achieved from the unsubstituted diamines by way of N-tert-butoxycarbonyl (Boc) substituted imidazolidines (tetrahydroimidazoles) and pyrimidines (hexahydro-1,3-diazines), which were treated with sec-butyllithium to effect deprotonation alpha- to the N-Boc group, followed by addition of an electrophile to give substituted products that could be hydrolysed under acidic conditions to give the substituted 1,2- or 1,3-diamines. Use of the chiral ligand (-)-sparteine promoted asymmetric deprotonation of the imidazolidine substrates to give, after hydrolysis, enantiomerically enriched 1,2-diamines.
authors.affiliation: School of Chemistry, University of Exeter, Stocker Road, Exeter, UK EX4 4QD.
authors.forename: Neil J
authors.initials: NJ
authors.lastname: Ashweek
authors.forename: Iain
authors.initials: I
authors.lastname: Coldham
authors.forename: Thomas F
authors.initials: TF
authors.lastname: Haxell
authors.forename: Steven
authors.initials: S
authors.lastname: Howard
mesh_terms: D003959:Diamines / Q000138:chemical synthesis*; D007093:Imidazoles / Q000737:chemistry*; D011743:Pyrimidines / Q000737:chemistry*
chemical_list: D003959:Diamines; D007093:Imidazoles; D011743:Pyrimidines