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。
Self-Assembling Neodymium/Sodium Heterobimetallic Asymmetric Catalyst Confined in a Carbon Nanotube Network
works better: A self‐assembling heterobimetallic catalyst, comprised of a Nd/Na/amide ligand confined in an entangled multiwalled carbon nanotube (MWNT) network, outperforms the unconfined catalyst in anti‐selective catalytic asymmetric nitroaldol reactions. The confined catalyst could be used repeatedly through simple filtration, and was applied to a concise enantioselectivesynthesis of anacetrapib
密闭猫的工作效果更好:一种由Nd / Na /酰胺配体组成的自组装杂双金属催化剂,该催化剂被限制在纠缠的多壁碳纳米管(MWNT)网络中,在反选择性催化不对称硝基醛缩合反应中,其性能优于无侧限催化剂。受限的催化剂可通过简单过滤重复使用,并用于anacetrapib的简明对映选择性合成。
Chiral Tetraaminophosphonium Salt-Mediated Asymmetric Direct Henry Reaction
作者:Daisuke Uraguchi、Sawako Sakaki、Takashi Ooi
DOI:10.1021/ja075152+
日期:2007.10.1
Chiral tetraaminophosphonium salts 1 possessing the phosphorus-centered [5.5]-spirocyclic core have been designed and synthesized in a single step from L-valine-derived diamine. The three-dimensional molecular structure was successfully verified by the single-crystal X-ray diffraction analysis, which also identified a secondary interaction between the phosphonium cation and chloride ion via double hydrogen-bonding. The potential of this novel onium salt as a chiral organic molecular catalyst has been demonstrated in an application to asymmetric direct Henry reaction.
Preparation of Nd/Na heterogeneous catalyst from bench-stable and inexpensive Nd salt for an anti-selective catalytic asymmetric nitroaldol reaction
a highly efficient heterogeneouscatalyst for an anti-selective catalytic asymmetric nitroaldol reaction. Nd alkoxide is sensitive to moisture, expensive, and scarce, making it difficult to use the Nd/Na catalyst in large-scale applications. Herein we describe a new protocol that allows for catalyst preparation from bench-stable and inexpensive NdCl3·6H2O with comparable catalytic activity.