Enantioselective addition of dimethylzinc to aldehydes catalyzed by N-substituted mandelamide-Ti(IV) complexes

Catalytic Enantioselective Addition of Me2Zn to Isatins

“…1.2 M Me 2 Zn solution in toluene was purchased from Acros (Geel, Belgium). Chiral α-hydroxyamides were prepared as described in the literature [35]. Commercially available isatins were used as received.…”

“…Nevertheless, only the group of Shibashaki [34] described just one example of the enantioselective addition of Me2Zn catalyzed by a proline-derived aminodiol ligand, obtaining the corresponding 3-hydroxy-3-methyl-2-oxindole in 82% yield and 88:12 enantiomeric ratio. In view of this lack of methodologies for the synthesis of such compounds, we decide to study the asymmetric addition of Me2Zn to isatins catalyzed by α-hydroxyamides derived from (S)-(+)-mandelic acid as chiral ligands [35][36][37][38][39][40]. Scheme 1.…”

Effect of microwave heating in the asymmetric addition of dimethylzinc to aldehydes

“…The absolute configuration of the products was determined by comparison of the sign of the optical rotation with the literature data [24,25].…”

Highly enantioselective addition of dimethylzinc to arylaldehydes catalyzed by (2S)-1-ferrocenyl-methylaziridin-2-yl(diphenyl)methanol

“…In recent years, the enantioselective addition of dimethylzinc to aldehydes has received a special attention in the presence of catalytic amounts of chiral ligands. [6][7][8][9][10][11][12] In 2005, a-hydroxy amide 1 was synthesized and used as a chiral ligand for asymmetric addition of Me 2 Zn to aromatic aldehydes with good enantioselectivity by means of titanium isopropoxide. 6 showed excellent asymmetric induction for the addition of Me 2 Zn to aldehydes.…”