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
Synthesis of chiral salalen ligands and their in-situ generated Cu-complexes for asymmetric Henry reaction
作者:Ashish Dixit、Pramod Kumar、Surendra Singh
DOI:10.1002/chir.23019
日期:2018.12
Chiral salalen ligands derivedfrom (S)‐proline and derivatives of salicyaldehydes were synthesized, and their in‐situ generated Cu (II) complexes were evaluated in the asymmetric Henry reaction. Salalen ligand of different substituents on the phenyl moiety showed remarkable effect on the enantioselectivity of nitro‐aldol product of 4‐nitrobenzaldehyde and nitromethane. Cu (II) complex generated in
合成了衍生自(S)-脯氨酸和水杨醛衍生物的手性Salalen配体,并在不对称Henry反应中评估了它们原位生成的Cu(II)配合物。苯基部分上不同取代基的Salalen配体对4-硝基苯甲醛和硝基甲烷的硝基羟醛产物的对映选择性表现出显着影响。与(S)-2-(叔丁基)-6(((2-((((2-羟基-3-甲基苄基)氨基)甲基)吡咯烷烃-1-基)甲基)生成的Cu(II)络合物苯酚(10 mol%)和Cu(OAc)2 .H 2O(10 mol%)被发现是4-硝基苯甲醛与硝基甲烷之间硝基-羟醛反应的较好催化剂,40小时后,在35°C下,异丙醇中的相应产物收率为85%,对映体过量(ee)为88%。还以不同的取代的苯甲醛用于亨利反应的催化剂和相应的产物以22%至99%的产率和66%至92%的ee获得。4-硝基苯甲醛与前手性硝基乙烷的亨利反应产生抗选择性产物(dr = 79/21; anti / syn),收率为91%,ee为80%。
Synthesis of Chiral 1,3-Diamines Derived from cis-2-Benzamidocyclohexanecarboxylic Acid and Their Application in the Cu-Catalyzed Enantioselective Henry Reaction
作者:Koichi Kodama、Kazuyuki Sugawara、Takuji Hirose
DOI:10.1002/chem.201102136
日期:2011.11.25
decrease in product enantioselectivity caused by spontaneous retro‐Henryreaction, which was suppressed by conducting the reaction at 0 °C. This versatile reaction afforded various β‐nitroalcohols in excellent yields and enantioselectivities (up to 98 % yield, 91 % enantiomeric excess) under the optimized reaction conditions. The chiral induction mechanism was explained on the basis of a previously
Enantio- & chemo-selective preparation of enantiomerically enriched aliphatic nitro alcohols using Candida parapsilosis ATCC 7330
作者:Sowmyalakshmi Venkataraman、Anju Chadha
DOI:10.1039/c5ra13593a
日期:——
asymmetric reduction of aliphaticnitroketones was carried out in water with ethanol as cosolvent and glucose as cosubstrate using the whole cells of Candida parapsilosis ATCC 7330 in much lesser time (4 h). For the first time, the biocatalytic asymmetric reduction of the following ketones is reported here: 1-nitro-butan-2-one, 1-nitro-pentan-2-one, 3-methyl-1-nitro-butan-2-one and 1-cyclohexyl-2-nitroethanone
Asymmetric Henry Reactions Catalyzed by Metal Complexes of Chiral Boron-Bridged Bisoxazoline (borabox) Ligands
作者:Aurélie Toussaint、Andreas Pfaltz
DOI:10.1002/ejoc.200800570
日期:2008.9
Metalcomplexes of boron-bridgedbisoxazolines (boraboxligands) were evaluated as catalysts for the Henryreaction. Copper(II) complexes induced high enantio- and diastereoselectivity in reactions with nitroethane and nitropropane. The amount of base added had a strong influence on the formation of the chiralcomplex and the enantioselectivity. Comparison with the corresponding dimethylmethylene-bridged