Discovery and development of efficient catalytic asymmetric methods for the preparation of nonracemic amines is an important objective in organic synthesis. In this context, there have been notable advances involving catalytic enantioselective hydrogenations and hydrogen transfer reactions involving imine1 and enamine substrates. 2 Protocols for catalytic enantioselective alkylations of imines have also emerged. Earlier reports include the catalytic enantioselective additions of alkyllithiums, 3 promoted by chiral amines, in up to 82% ee. More recently, Tomioka4 and co-workers disclosed Cu-catalyzed asymmetric additions of Et2Zn to N-tosylimines, while research in our laboratories has resulted in the development of a method for Zr-catalyzed asymmetric additions of a range of alkylzinc reagents to o-anisidyl imines. 5 Nonetheless, the large majority of the above advances (both hydrogenations and alkylations), deals with transformations of aromatic imines and enamines. 6 Herein, we report the results of our studies regarding the Zr-catalyzed asymmetric addition of alkylzincs to aliphatic imines by a single-vessel, three-component catalytic asymmetric procedure that obviates the need for isolation of unstable imine starting materials (Scheme 1). The requisite chiral ligands are peptide-based7 and can be synthesized through coupling (and reduction) of commercially available aromatic aldehydes and amino acids valine and phenylalanine. 8 Our initial attempts to examine the catalytic alkylations of aliphatic o-anisidyl imines were thwarted by their lack of stability upon isolation. In contrast to the derived aromatic imines, it is likely that the presence of the acidic R-protons, together with the activating effect of the o-anisidyl unit, leads to formation of the enamines and the corresponding homocoupling products (eg, aldol-and Mannich-type additions). 9 To circumvent the above complication, we set out to examine the possibility of threecomponent asymmetric amine synthesis involving imine formation from an appropriate aldehyde and o-anisidine, followed by in situ catalytic alkylation. The viability of such an approach was first investigated with aromatic aldehydes. As illustrated in entry 1 of Table 1, we established that treatment of benzaldehyde with o-anisidine, 10 mol% dipeptide Schiff base ligand 1 and Zr (Oi-Pr) 4 ‚HOi-Pr and six equiv of Et2Zn leads to the facile formation of amine 2 in 82% ee and 90% isolated yield. 10 Reaction efficiency and enantioselectivity improved when dipeptide amine 3 was employed (entry 2). Two more examples, involving

2-furaldehyde and 3-pyridine carboxaldehyde11 are illustrated in Table 1 (entries 3-4). Additional issues regarding the data in Table 1 merit mention:(i) In all cases shown, analysis of the 400 MHz1H NMR spectra did not indicate any products from alkylations of aldehydes (< 2%).(ii) Although appreciable asymmetric induction is observed, the selectivities shown in Table 1 are somewhat lower than those obtained with purified imine substrates. 5