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。
CHIRAL TETRAAMINOPHOSPHONIUM SALTS, CATALYST FOR ASYMMETRIC SYNTHESIS AND METHOD FOR PRODUCING CHIRAL beta-NITROALCOHOL
申请人:OOI Takashi
公开号:US20090131716A1
公开(公告)日:2009-05-21
A chiral tetraaminophosphonium salt represented by formula (1) and a method for producing chiral β-nitroalcohol comprising reacting an aldehyde or a ketone and a nitroalkane in the presence of the chiral tetraaminophosphonium salt represented by formula (1) and a base, or in the presence of a conjugated base of the chiral tetraaminophosphonium salt represented by formula (1):
wherein R
1
to R
4
are independently a hydrogen atom or a monovalent hydrocarbon group; and, R
1
and R
2
are different groups or R
3
and R
4
are different groups.
A Heterobimetallic Pd/La/Schiff Base Complex foranti-Selective Catalytic Asymmetric Nitroaldol Reactions and Applications to Short Syntheses of β-Adrenoceptor Agonists
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.