A Bench-Stable Homodinuclear Ni<sub>2</sub>−Schiff Base Complex for Catalytic Asymmetric Synthesis of α-Tetrasubstituted <i>anti</i>-α,β-Diamino Acid Surrogates
Catalyticasymmetric direct Mannich-type reactions of α-substituted nitroacetates using a new bench-stable homodinuclear Ni2−Schiff base 1b complex are described. The Ni2−1b complex gave Mannich products, precursors for anti-α,β-diamino acids with an α-tetrasubstituted carbon stereocenter, in >99−91% ee. The Ni2−1b complex was also applicable to direct Mannich-type reactions of malonates and β-keto
Palladium-Catalyzed Asymmetric [3+2] Cycloaddition of Trimethylenemethane with Imines
作者:Barry M. Trost、Steven M. Silverman、James P. Stambuli
DOI:10.1021/ja0753389
日期:2007.10.1
The transition metal-catalyzed trimethylenemethane [3+2] cycloaddition provides a direct route to functionalized heterocycles. Herein, we describe a catalytic, asymmetric protocol for the reaction between 3-acetoxy-2-trimethylsilylmethyl-1-propene and various imines. The corresponding pyrrolidines were obtained in excellent yields and enantioselectivities making use of the novel phosphoramidite L10
A highly enantio- and diastereoselective catalytic asymmetric Mannich-type reaction of acyanoketones and N-Boc imines promoted by an amide ligand/Sc(OiPr)(3) catalyst is described. The similar reaction outcome is obtained with/without precomplexation of catalyst, suggesting that reaction i components in a non-ordered conglomerate mixture orchestrate to form an ordered transition state during the reaction. Spectroscopic data and Eyring plot are consistent with this assumption.
Davis, Tyler A.; Wilt, Jeremy C.; Johnston, Jeffrey N., Journal of the American Chemical Society, 2010, vol. 132, p. 2880 - 2882
作者:Davis, Tyler A.、Wilt, Jeremy C.、Johnston, Jeffrey N.