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.