Asymmetric [3+2] Cycloaddition of Azomethine Ylides Catalyzed by Silver(I) Triflate with a Chiral Bipyrrolidine-Derived Phosphine Ligand
作者:Zhen-Jiang Xu、Chi-Ming Che、Xin Gu、Vanessa Lo
DOI:10.1055/s-0032-1316779
日期:——
bipyrrolidine-derived phosphine ligands L1 and L2 were synthesized. The ‘AgOTf + L1’ protocol catalyzes the asymmetric [3+2] cycloaddition of azomethineylides with alkenes to give highly substituted pyrrolidines in good yields (up to 90%) with moderate to high diastereoselectivities (up to >19:1 dr) and enantioselectivities (up to 76%). Two novel chiral bipyrrolidine-derived phosphine ligands L1 and L2 were synthesized
Highly Enantioselective Ag(I)-Catalyzed [3 + 2] Cycloaddition of Azomethine Ylides
作者:James M. Longmire、Bin Wang、Xumu Zhang
DOI:10.1021/ja025969x
日期:2002.11.1
A highly reactive Ag(I)-catalyzed [3 + 2] cycloaddition of azomethineylides is founded using AgOAc as the catalytic precursor and phosphines as ligands. Using a new bis-ferrocenyl amide phosphine (FAP) as the ligand, we found that high enantioselectivities (up to 97% ee) have been achieved in the [3 + 2] cycloaddition of azomethineylides. Up to four stereogenic centers can be established in this
Bifunctional AgOAc-Catalyzed Asymmetric [3 + 2] Cycloaddition of Azomethine Ylides
作者:Wei Zeng、Yong-Gui Zhou
DOI:10.1021/ol0520370
日期:2005.10.1
[reaction: see text] A bifunctional AgOAc-catalyzed asymmetriccycloaddition of azomethineylides with electronic-deficient alkenes was developed using ferrocenyloxazoline-derived N,P ligands. The reactive metal-bound azomethineylide dipole is formed by the deprotonation with acetate, and extra base is not necessary. The reactions proceed with high enantioselectivity. This method provides an efficient