Asymmetric hydroamination/cyclization catalyzed by group 4 metal complexes with chiral biaryl-based ligands

Group 4 metal complexes based on chiral biaryl ligands are readily prepared by a convenient amine elimination procedure, and they are efficient catalysts for the asymmetric hydroamination/cyclization of aminoalkenes. The biaryl-based ligands are highly modular enabling facile tuning of the catalyst reactivity and selectivity. The corresponding heterocyclic products have been obtained in excellent enantiomeric excesses (up to 93%) using sterically hindered C-2-symmetric titanium and zirconium mesitoylamidate complexes such as [1,1'-(C10H10)(2)-2,2'-{NCO(2,4,6-Me3C6H2)}(2)]M(NMe2)(2) (M = Ti, Zr). These results are presented in this short review. (C) 2010 Elsevier B.V. All rights reserved.