Efficient Asymmetric Copper(I)-Catalyzed Henry Reaction Using Chiral N-Alkyl-C1-tetrahydro-1,1′-bisisoquinolines
作者:Yao Qiong ji、Gao Qi、Zaher M. A. Judeh
DOI:10.1002/ejoc.201100579
日期:2011.7.14
closely related chiral N-alkyl-C1-tetrahydro-1,1′-bisisoquinoline ligands only differing in the steric bulk of the alkyl groups has been examined in the asymmetricHenry reaction. A complex derived from the (R)-N-methyl-1′,2′,3′,4′-tetrahydro-1,1′-bisisoquinoline and copper(I) chloride proved to be a very efficient catalyst system that can promote the reaction of a wide range of aromatic and aliphatic
Enantioselective catalysts for the Henry reaction: fine-tuning the catalytic components
作者:Edwin C. Constable、Guoqi Zhang、Catherine E. Housecroft、Markus Neuburger、Silvia Schaffner、Wolf-D. Woggon、Jennifer A. Zampese
DOI:10.1039/b9nj00243j
日期:——
Catalysts for the asymmetric Henry reaction involving 1,6-bis(3-ethoxy-2-hydroxyphenyl)-(3S,4S)-(−)-diphenyl-2,5-diazahexane (H22) and copper salts have been investigated. Conditions for the conversion of 4-nitrobenzaldehyde to 2-nitro-1-(4-nitrophenyl)ethanol by reaction with nitromethane have been optimized (5 mol% H22, 10 mol% CuI, THF, 295 K and 2 hours or 273 K and 12 hours) resulting in 99% yield and 90–92% ee. These catalytic conditions are effective for other aromatic aldehydes containing electron-withdrawing substituents, and for pyridine carbaldehydes; representative aliphatic aldehydes were converted to the respective β-hydroxynitro derivatives with good enantioselectivities, and in moderate yields. These catalytic conditions were found to be ineffective for simple aromatic aldehydes or those containing electron-releasing substituents.
Enantioselective Henry reaction catalyzed by a C2-symmetric bis(oxazoline)–Cu(OAc)2·H2O complex
作者:Sandeep K. Ginotra、Vinod K. Singh
DOI:10.1039/b714153j
日期:——
A C(2)-symmetric diethyl (i)Pr-bis(oxazoline)-Cu(OAc)(2).H(2)O was found to be an efficient catalyst for catalyzing an enantioselective Henry reaction between nitromethane and various aldehydes to provide beta-hydroxy nitroalkanes with high chemical yields (up to 95%) and enantiomeric excesses (up to 97%).
Chiral oxazoline ligands containing a 1,2,4-triazine ring and their application in the Cu-catalyzed asymmetric Henry reaction
作者:Ewa Wolińska
DOI:10.1016/j.tet.2013.06.084
日期:2013.9
Eleven members of newligand class incorporating a chiral oxazoline and a 1,2,4-triazine ring have been synthesized via Pd-catalyzed amination reaction of 3-halo-1,2,4-triazines with 2-(o-aminophenyl)oxazolines. Buchwald–Hartwig amination of 3-halo-1,2,4-triazines was investigated to establish the best conditions for synthesis of the title ligands. Catalytic activity of the newligands was evaluated in
Asymmetric Henry reactions catalyzed by metal complexes of chiral oxazoline based ligands
作者:A. Ebru Aydin、Seda Yuksekdanaci
DOI:10.1016/j.tetasy.2012.11.022
日期:2013.1
Chiral oxazolines have been synthesized from norephedrine and pyrrole nitrile or benzoyl chloride and applied to the catalytic asymmetricHenryreactions of p-nitro aldehydes with nitromethane to provide β-hydroxy nitroalkanols in high conversion (up to 92%). The reaction was then optimized in terms of the metal, solvent, temperature, and amount of chiralligand. The corresponding catalyst with Cu(OTf)2