Aldol Addition-Cyclization Reaction Cascade on a Platform of Chiral Ni(II) Complex of Glycine Schiff Base

Abstract

Using platform of a new type of chiral Ni(II) complex of glycine Schiff base we designed addition-cyclization reaction cascade to explore aspects of kinetic/thermodynamic formation of the corresponding (S)(2S,3S)/(S)(2S,3R) diastereomers. It was found that the final lactone products reflect the thermodynamic stereocontrol due to much greater rates of the reversible aldol addition vs. subsequent cyclization step. The observed 4/1 (S)(2S,3S)/(S)(2S,3R) diastereoselectivity in the reactions of new type of (S)-Ni(II) complexes constitute an improvement over the previously reported 1.7/1 ratio.