Design and Synthesis of Chiral Imidazolidine-Pyridine Ligands
作者:Takayoshi Arai、Kuniko Suzuki
DOI:10.1055/s-0029-1218311
日期:2009.12
Condensation of chiral diamines and aldehydes gave a series of chiral imidazolidine-pyridine compounds with high diastereoselectivities. The ability of these compounds to act as chiral ligands was examined in the catalytic Henry reaction.
A 3,3'-bis(aminoimino)BINOL ligand was newly designed and synthesized for the formation of a trinuclear Zn complex upon reaction with Zn(OAc)2. Using the harmony of the tri-zinc atoms, 1 mol% Zn3(OAc)4-3,3'-bis(aminoimino)binaphthoxide catalyzed asymmetriciodolactonization in up to 99.9% ee.
Stereocontrolled Construction of Spirooxindole-Containing 5,6,7,8-Tetrahydropyrrolo[1,2-<i>a</i>]pyridine via Michael/Friedel–Crafts Domino Reaction Promoted by Secondary Amine-Squaramide
作者:Pengxuan Yin、Zijie Zhou、Lingsheng Shi、Chengzhi Xiang、Ling Ye、Min Han、Zhichuan Shi、Zhigang Zhao、Xuefeng Li
DOI:10.1021/acs.orglett.4c00073
日期:2024.3.22
An asymmetric Michael/Friedel–Crafts cascadereaction with Morita–Baylis–Hillman (MBH) nitroallylic esters and 3-pyrrolyloxindoles has been developed for the stereoselective construction of spirooxindole-containing tetrahydroindolizines. A range of tetracyclic scaffolds possessing three consecutive chiralcenters, including an all-carbonquaternary stereocenter, were generated in 53–85% isolated yields
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.