Catalytic Asymmetric exo′-Selective [3+2] Cycloaddition of Iminoesters with Nitroalkenes
作者:Takayoshi Arai、Naota Yokoyama、Asami Mishiro、Hiroyasu Sato
DOI:10.1002/anie.201004098
日期:2010.10.18
Under control: A chiral imidazoline–aminophenol/Ni(OAc)2 complex promotes the first catalyticasymmetric exo′‐selective [3+2] cycloaddition of iminoesters and nitroalkenes. Thermodynamic control over the stepwise Michael/Mannich cyclization steps gives the adducts in up to 99 % ee.
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
Ag/ThioClickFerrophos catalyzed highly enantioselective 1,3-dipolar cycloaddition of azomethine ylides with alkenes
作者:Kenta Shimizu、Kenichi Ogata、Shin-ichi Fukuzawa
DOI:10.1016/j.tetlet.2010.07.085
日期:2010.9
A silver(I)/ThioClickFerrophos complex catalyzed the endo selective asymmetric 1,3-dipolarcycloaddition reaction of methyl N-benzylideneglycinate (the source of azomethine ylides) with α,β-unsaturatedesters and maleimides to give the endo-2,4,5- and 2,3,4,5-substituted pyrrolidines in good yields with high enantioselectivities (up to 99% ee). The complex also effectively catalyzed the endo selective
Chiral Bis(imidazolidine)pyridine−Cu(OTf)<sub>2</sub>: Catalytic Asymmetric Endo-Selective [3 + 2] Cycloaddition of Imino Esters with Nitroalkenes
作者:Takayoshi Arai、Asami Mishiro、Naota Yokoyama、Kuniko Suzuki、Hiroyasu Sato
DOI:10.1021/ja100265j
日期:2010.4.21
The novel C-2-symmetric bis(imidazolidine)pyridine (PyBidine) ligand was easily synthesized in a single condensation of 2,6-pyridyl aldehyde and optically active (S,S)diphenylethylenediamine. In the C-2-symmetric PyBidine-Cu(OTf)(2) complex, imidazolidine rings act as "chiral fences" to shield the first and third quadrants. Use of the PyBidine-Cu(OTf)(2) complex as a catalyst enabled the highly endo-selective reaction of imino esters and nitroalkenes to give the adducts in up to 99% ee.