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
Asymmetric Henry reactions of aldehydes with various nitroalkanes catalyzed by copper(II) complexes of novel chiral<i>N</i>-monoalkyl cyclohexane-1,2-diamines
作者:Fei Liu、Shaohua Gou、Lei Li
DOI:10.1002/aoc.3107
日期:2014.3
2‐diamine (3g), the reaction was optimized in terms of the metal ion, temperature, solvent and base. Further experiments indicated that the complex, 3g–Cu(OAc)2, was an efficient catalyst in the asymmetricHenryreaction between different aldehydes and nitromethane, and the desired products have been obtained with high chemical yields (up to 99%) and high enantiomeric excess (up to 93%). The optimized catalyst
A novel C1-symmetric dinitrogen ligand was synthesized in high yield from commercially available (1R,2R,3R,5S)-(-)-isopinocampheylamine and 1-methyl-2-imidazolecarboxaldehyde. In combination with Cu(OAc)2H2O, this new ligand promote the reaction between nitromethane and aliphatic aldehydes with high yields (up to 97%) and moderate enantioselectivities (up to 67% ee). The reactions with benzaldehyde
Atom‐economic synthesis: The syn‐ and highlyenantioselective Henry reactions of aliphaticaldehydescatalyzed by a readilyavailable β‐amino alcohol copper catalyst were developed and successfully utilized in the synthesis of safingol. The ligand could be easily recovered without any racemization (see scheme).