Zinc metal–organic frameworks: efficient catalysts for the diastereoselective Henry reaction and transesterification
作者:Anirban Karmakar、M. Fátima C. Guedes da Silva、Armando J. L. Pombeiro
DOI:10.1039/c4dt00219a
日期:——
Three new amidoterephthalate ligands are utilized to synthesize three new zinc(ii) metal–organic frameworks which act as heterogeneous catalysts for the diastereoselective nitroaldol (Henry) and transesterification reactions.
New Highly Asymmetric Henry Reaction Catalyzed by CuII and aC1-Symmetric Aminopyridine Ligand, and Its Application to the Synthesis of Miconazole
作者:Gonzalo Blay、Luis R. Domingo、Victor Hernández-Olmos、José R. Pedro
DOI:10.1002/chem.200800069
日期:2008.5.19
A new catalytic asymmetricHenryreaction has been developed that uses a C(1)-symmetric chiral aminopyridineligand derived from camphor and picolylamine. A variety of aromatic, heteroaromatic, aliphatic, and unsaturated aldehydes react with nitromethane and other nitroalkanes in the presence of DIPEA (1.0 equiv), Cu(OAc)(2)*H(2)O (5 mol %), and an aminopyridineligand (5 mol %) to give the expected
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%。
Copper Complex of Aminoisoborneol Schiff Base Cu
<sub>2</sub>
(SBAIB‐d)
<sub>2</sub>
: An Efficient Catalyst for Direct Catalytic Asymmetric Nitroaldol (Henry) Reaction
new bifunctional coppercomplex of the aminoisoborneolSchiffbase – Cu2(SBAIB‐d)2 – has been developed for the effective directcatalyticasymmetricHenryreaction. One mol% of this catalyst produces the expected Henry products in high yields (up to 99%) with excellent enantioselectivities (up to 98% ee). The utility of the present catalyst was also extended to the Henryreaction with nitroethane
preparation in THF, a heterogeneous mixture developed and centrifugation of the suspension allowed for separation of the precipitate, which contained the active catalyst and which could be stored for at least 1 month without any loss of catalytic performance. The precipitate promoted a nitroaldol (Henry) reaction for a broad range of nitroalkanes and aldehydes under heterogeneous conditions, affording
描述了由 Nd(5)O(O(i)Pr)(13)、基于酰胺的配体和 NaHMDS(六甲基二硅肼钠)组成的异双金属催化剂促进的抗选择性催化不对称硝基醛醇反应的全部细节。酰胺基配体的系统合成和评估导致最佳配体1m的鉴定,这为Nd/Na异质双金属配合物提供了合适的平台。在 THF 中制备催化剂的过程中,形成了一种非均相混合物,悬浮液的离心允许沉淀物分离,其中含有活性催化剂并且可以储存至少 1 个月而不会损失任何催化性能。沉淀促进了多种硝基烷烃和醛在非均相条件下的硝基醛醇 (Henry) 反应,得到相应的 1, 2-硝基烷醇以高度抗选择性(高达 anti/syn = >40/1)和对映选择性方式(高达 98% ee)。电感耦合等离子体 (ICP) 和 X 射线荧光 (XRF) 分析表明,沉淀确实包含钕和钠,高分辨率 ESI TOF MS 光谱法进一步支持了这一点。