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 C2-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.