Synthesis of Chiral Tetrahydroisoquinoline and C 2-Symmetric Bistetrahydroisoquinoline Ligands and Their Application in the Enantioselective Henry Reaction
作者:Zaher Judeh、Duc Khong
DOI:10.1055/s-0035-1561634
日期:——
rigid chiral tetrahydroisoquinoline THIQ–Cu(OAc)2·H2O complex successfully catalyzed the enantioselective Henry reaction between various aldehydes and nitromethane and gives the β-nitro alcohol adducts in up to 96% yield and 80% ee. Application of chiral tetrahydroisoquinoline and bistetrahydroisoquinoline scaffolds in asymmetric reactions is limited by the inefficient synthesis of their chiral structural
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%。
Pyrrole Macrocyclic Ligands for Cu-Catalyzed Asymmetric Henry Reactions
5′-(alkane-2,2-diyl)bis(1H-pyrrole-2-carbaldehydes). These macrocycles, differing for the alkyl/aryl meso-substituents, were used as ligands in the copper-catalyzed Henry reactions of aromatic and aliphatic aldehydes with nitroalkanes. In the optimized experimental conditions, the condensations of nitromethane and aromatic and aliphatic aldehydes in the presence of catalytic amounts of copper diacetate and
A new class of chiral sulfoxideâSchiff base ligands has been developed by the rational combination of two privileged chiral backbones. These sulfoxideâSchiff base ligands were found to be highly efficient for Cu-catalyzed asymmetric Henry reactions (up to 98% yield and 96% ee).
A new type of L-Tertiary leucine-derived ligand: Synthesis and application in Cu(II)-catalyzed asymmetric Henry reactions
作者:Zedong Cai、Ting Lan、Pengfei Ma、Jingfang Zhang、Qingqing Yang、Wei He
DOI:10.1016/j.tet.2019.130469
日期:2019.8
of Schiff bases derivedfrom amino acids were developed as chiral ligands for Cu(II)-catalyzed asymmetric Henryreactions. The optimum ligand 7d exhibited outstanding catalytic efficiency in the Cu(II)-catalyzed asymmetric Henry additions of four nitroalkanes to different kinds of aldehydes to produce 76 desired adducts in high yields (up to 96%) with excellent enantioselectivities, up to 99% enantiomeric