Cu-catalyzed asymmetric [3+2] cycloaddition of α-iminoamides with activated olefins
作者:María González-Esguevillas、Javier Adrio、Juan C. Carretero
DOI:10.1039/c2cc17149j
日期:——
A variety of 2-amido pyrrolidines, including Weinreb-type amides, have been prepared with very high exo diastereoselectivity and enantioselectivitiy in the reaction of alpha-iminoamides with activated alkenes catalyzed by Cu(I)-Segphos ligands.
Switching Diastereoselectivity in Catalytic Enantioselective (3+2) Cycloadditions of Azomethine Ylides Promoted by Metal Salts and Privileged Segphos-Derived Ligands
作者:Guilherme S. Caleffi、Olatz Larrañaga、Marcos Ferrándiz-Saperas、Paulo R. R. Costa、Carmen Nájera、Abel de Cózar、Fernando P. Cossío、José M. Sansano
DOI:10.1021/acs.joc.9b00267
日期:2019.9.6
Catalytic enantioselective 1,3-dipolar cycloaddition between imino esters and electrophilic alkenes, employing chiral metal complexes derivedfrom copper(I) and silver(I) salts and (S)-DM- or (S)-DTBM-Segphos as ligands produces diastereodivergently exo- or endo-cycloadducts, respectively. The effect of the functional group of the dipolarophile and the fine tuning of the catalyst plays an important
A Highly Enantioselective Copper/Phosphoramidite-Thioether-Catalyzed Diastereodivergent 1,3-Dipolar Cycloaddition of Azomethine Ylides and Nitroalkenes
full control of the absolute and relative stereochemical configurations. Here, we report the application of our previously developed modular phosphoramidite‐thioether ligands for the copper‐catalyzed diastereodivergent asymmetric 1,3‐dipolar cycloaddition of azomethine ylides and nitroalkenes. Our catalytic system enables wide substrate scope, great stereochemical control, and high reaction efficiency
enantioselective strategy for the synthesis of optically pure nitro‐substituted pyrrolidines. In addition, the experimental results with regard to the carbon stereogenic center as well as the amide stereochemistry confirmed the potential of hemilabile atropisomers as chiral ligand in catalyticasymmetric [3+2] cycloaddition reaction.
Highly Enantioselective Copper(I)−Fesulphos-Catalyzed 1,3-Dipolar Cycloaddition of Azomethine Ylides
作者:Silvia Cabrera、Ramón Gómez Arrayás、Juan C. Carretero
DOI:10.1021/ja0552186
日期:2005.11.30
The catalyst system formed by Cu(CH3CN)4ClO4 and the planar chiral P,S-ligand Fesulphos behaves as a very efficient chiral Lewis acid in the catalytic asymmetric 1,3-dipolarcycloaddition of azomethine ylides. This catalyst shows a remarkable reactivity at low catalyst loading (0.5-3 mol %), affording in good yields the endo adducts with exceptional levels of enantioselectivity (up to >99% ee). This