Asymmetric Cycloadditions of Acyclic Carbonyl Ylides with Aldehydes Catalyzed by a Chiral Binaphthyldiimine-Ni(II) Complex: Enantioselective Synthesis of 1,3-Dioxolanes and Mechanistic Studies by DFT Calculations.

Chiral binaphthyldiimine-Ni(II)-catalyzed asymmetric 1,3-dipolar cycloaddition reactions between acyclic carbonyl ylides generated from donor-acceptor oxiranes and aldehydes are reported. Both aromatic and aliphatic aldehydes could be used as dipolarophiles, providing -1,3-dioxolanes with high diastereo- and enantioselectivities. On the basis of mechanistic studies, a monomeric chiral Ni(II) complex was hypothesized to act as the active species for the cycloaddition.

Enantioselective Oxidative Ring-Opening Reaction of Aziridines with α-Nitroesters Using Cinchona Alkaloid Amide/Nickel(II) Catalysts.

The enantioselective oxidative ring-opening reaction of aziridines with α-nitroacetates has been developed. Good yields and enantioselectivity were observed for the reaction of various aziridines using a novel cinchona alkaloid amide/NiBr catalyst. Both enantiomers of products could be obtained by using pseudoenantiomeric chiral catalysts.