Stereoselective C9 Carbon−Carbon Couplings of Quinine: Synthesis and Conformational Analysis of New C2-Symmetric Dimers
摘要:
An unexpected stereoselective direct dimerization Occurred when 9-quinine halide was treated with butyllithium. The reaction of either (9S)- or (9R)-chloroquinine gave the same C-2-symmetric dimer with 9R configuration (X-ray structure). A tentative mechanism involving radical recombination is discussed. This highly congested dimer forms two atropisomers, and their reversible interconversion was studied by NMR. Another C-2-symmetric (9S)-quinine dinner connected solely by carbon-carbon bonds was obtained by the stereoselective coupling of bis(arylbromomagnesium) derivative with (9S)-chloroquinine.
Tricyclic Quaternary Ammonium Salts Derived from <i>Cinchona</i> Alkaloids
作者:Przemysław J. Boratyński、Rafał Kowalczyk、Anna Kobylańska、Julia Bąkowicz
DOI:10.1021/acs.joc.6b02348
日期:2016.12.16
bridgehead nitrogen atoms are rare but an interesting class of compounds. Chiral quinuclidine derivative salts with fused five and six-membered rings (X-ray) were obtained via modification of Cinchona alkaloids. The ease of ring formation was dependent on its size, while even mild activation sufficed to close the five membered ring. On the other hand the systems with fused benzene and a six-membered ring
Giemsa; Halberkann, Chemische Berichte, 1921, vol. 54, p. 1186
作者:Giemsa、Halberkann
DOI:——
日期:——
Stereoselective C9 Arylation and Vinylation of <i>Cinchona</i> Alkaloids
作者:Przemysław J. Boratyński、Ilona Turowska-Tyrk、Jacek Skarżewski
DOI:10.1021/ol7026625
日期:2008.2.1
A simple and efficient method for the highly stereoselective C-9 arylation and vinylation of Cinchona alkaloids was developed. Both 9s- and 9R-chloroquinine with PhMgBr yielded 9S-phenylquinine (X-ray structure). The reactions with various aryl and vinyl Grignard reagents resulted in the series of 9S-aryl and vinyl alkaloid derivatives. The stereochemical outcome was rationalized by coordination of the magnesium atom to the quinuclidine nitrogen, thus directing the nucleophilic attack at the C-9 stereogenic center.
Stereoselective C9 Carbon−Carbon Couplings of Quinine: Synthesis and Conformational Analysis of New <i>C</i><sub>2</sub>-Symmetric Dimers
作者:Przemysław J. Boratyński、Ilona Turowska-Tyrk、Jacek Skarżewski
DOI:10.1021/jo801205n
日期:2008.9.19
An unexpected stereoselective direct dimerization Occurred when 9-quinine halide was treated with butyllithium. The reaction of either (9S)- or (9R)-chloroquinine gave the same C-2-symmetric dimer with 9R configuration (X-ray structure). A tentative mechanism involving radical recombination is discussed. This highly congested dimer forms two atropisomers, and their reversible interconversion was studied by NMR. Another C-2-symmetric (9S)-quinine dinner connected solely by carbon-carbon bonds was obtained by the stereoselective coupling of bis(arylbromomagnesium) derivative with (9S)-chloroquinine.
Heidelberger; Jacobs, Journal of the American Chemical Society, 1920, vol. 42, p. 1497