7499-29-8Relevant academic research and scientific papers
A flexible enantioselective approach to 3,4-dihydroxyprolinol derivatives by SmI2-mediated reductive coupling of chiral nitrone with ketones/aldehydes
Zhang, Hong-Kui,Xu, Shou-Qiang,Zhuang, Jia-Jia,Ye, Jian-Liang,Huang, Pei-Qiang
experimental part, p. 6656 - 6664 (2012/08/29)
A flexible enantioselective approach to polyhydroxylated prolinol derivatives was described, which is based on the samarium diiodide-mediated reductive coupling of the chiral nitrone (3S,4R)-8, derived from d-isoascorbic acid with aldehydes/ketones. Thereby, polyhydroxyprolinol derivatives 9a-e and 9h-j were obtained from aromatic ketones and aliphatic aldehydes in good to excellent yields of 65-91%. These reductive hydroxyalkylations are highly diastereoselective in establishing the C-4 stereogenic center. By this way, the asymmetric syntheses of (-)-8a-epi-swainsonine (4) and (-)-8,8a-di-epi- swainsonine (5) have been achieved.
Stereochemistry and Side Products in Reductive Coupling of Alkyl Aryl Ketones to 1,2-Dialkyl-1,2-diarylethylenes
Leimner, Juergen,Weyerstahl, Peter
, p. 3697 - 3705 (2007/10/02)
The reductive coupling of alkyl aryl ketones 1 - 3 and 7 - 9 by low valent titanium salts yields predominantly the (Z)-isomers of 11 - 13 and 17 - 19.Evidence is given by 1H NMR spectroscopy.This behavior can be explained by ?-complex formation of phenyl rings with Ti0.Severe steric hindrance, however, favors the (E)-isomers ( -> 14 and 15).Donor groups in p-position, particularly, give increasing amounts of pinacols, 23 - 27, which undergo rearrangement to the ketones 28 and 29.
