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
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).
Design of a Chiral Secondary Amine Ligand for Copper-Catalyzed anti-Selective Henry Reaction
作者:Takayoshi Arai、Akinori Joko、Katsuya Sato
DOI:10.1055/s-0034-1379607
日期:——
A series of chiral binaphthyl-containing diphenylethylenediamine (binaph-dpen) ligands was designed and synthesized for the copper-catalyzed asymmetric Henry reaction. The N-monobenzyl (S)-binaph-(R,R)-dpen ligand, with a secondaryamine portion, promoted the Cu(OAc)2-catalyzed Henry reaction with excellent enantioselectivity in an anti-selective manner.