Chiral 1,1′-binaphthylazepine derived amino alcohol catalyzed asymmetric Henry reaction
摘要:
The catalytic asymmetric Henry reaction of nitromethane to various aldehydes has been developed using a chiral binaphthylazepine derived amino alcohol and Cu(OAc)(2)center dot H2O as the catalyst. High yields and good enantioselectivities (up to 97% ee) were obtained for both aromatic and aliphatic aldehydes. Moreover, this catalytic system also works well for the diastereoselective Henry reaction to afford the corresponding adducts in up to 95:5 syn/anti selectivity and 95% enantioselectivity. (C) 2011 Elsevier Ltd. All rights reserved.
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
catalytic asymmetric Henry reaction has been developed with use of a sulfonyldiamine−CuCl complex as a catalyst. A series of new binaphthyl-containing sulfonyldiamine ligands (2a−h) were readily synthesized in two steps starting from commercially available chiral 1,2-diamines. The (R,R)-diamine-(R)-binaphthyl ligand (2d)−CuCl complex smoothly catalyzed the enantioselective Henry reaction with the assistance
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
diastereoselective Henry reaction of various aldehydes with nitroethane was developed using the guanidine-thioureabifunctional catalyst 1 (syn selectivity of 86:14 to 99:1 with 84–99 % ee). A variety of nitroalkanes was treated with unbranched and branched aldehydes and gave nitro alcohols with high syn diastereoselectivities (90:10 to 99:1) and high enantioselectivities (85–95 % ee). This reaction was successfully