Translating the Enantioselective Michael Reaction to a Continuous Flow Paradigm with an Immobilized, Fluorinated Organocatalyst
作者:Irina Sagamanova、Carles Rodríguez-Escrich、István Gábor Molnár、Sonia Sayalero、Ryan Gilmour、Miquel A. Pericàs
DOI:10.1021/acscatal.5b01746
日期:2015.11.6
enantioselective, continuous flow processes allowing either the multigram synthesis of a single Michael adduct over a 13 h period or the sequential generation of a library of enantiopure Michael adducts from different combinations of substrates (13 examples, 16 runs, 18.5 h total operation). A customized in-line aqueous workup, followed by liquid–liquid separation in flow, allows for product isolation
Michael addition of carbonyl compounds to nitroolefins under the catalysis of new pyrrolidine-based bifunctional organocatalysts
作者:A. Castán、R. Badorrey、J. A. Gálvez、P. López-Ram-de-Víu、M. D. Díaz-de-Villegas
DOI:10.1039/c7ob02798b
日期:——
the asymmetric Michael addition of carbonyl compounds to nitroolefins have been synthesised from homoallylamines, which are easily obtained from (R)-glyceraldehyde as a chiral precursor. Under optimal reaction conditions, these bifunctional organocatalysts showed a high catalytic efficiency (almost quantitative yield in most cases) and stereoselectivity in the Michael addition reactions of a variety
This Letter described the synthesis of the first diarylprolinol silyl ether-derived bifunctional thiourea organocatalysts. The catalysts were applied to the asymmetricMichaeladdition of aldehydes to nitroalkenes to give the desired adducts in good yields (up to 99%) with excellent enantioselectivities (up to 99% ee) and excellent diastereoselectivities (up to 99:1). The spatial placement of C-4 substituent
Synthesis of new pyrrolidine-based organocatalysts and study of their use in the asymmetric Michael addition of aldehydes to nitroolefins
作者:Alejandro Castán、Ramón Badorrey、José A Gálvez、María D Díaz-de-Villegas
DOI:10.3762/bjoc.13.59
日期:——
pyrrolidine-based organocatalysts with a bulky substituent at C2 were synthesized from chiral imines derivedfrom (R)-glyceraldehyde acetonide by diastereoselective allylation followed by a sequential hydrozirconation/iodination reaction. The new compounds were found to be effective organocatalysts for the Michael addition of aldehydes to nitroolefins and enantioselectivities up to 85% ee were achieved
active chiral moieties along the network. The hybrid material was studied by means of different characterization techniques (TGA, NMR and IR spectroscopy, chemical and elemental analyses, TEM, and textural measurements), verifying the stability and integrity of the asymmetric active sites in the solid. The hybrid material, HybPyr, is an excellent asymmetric heterogeneous and recyclable catalyst for enantioselective
基于硅质骨架 HybPyr 中包含的吡咯烷单元,合成了一种新型手性介孔杂化材料,并由特定的双甲硅烷基化前体整合到有机-无机结构中。在软合成条件下且在没有复杂的结构导向剂的情况下,氟化物溶胶-凝胶方法可以产生介孔结构,活性手性部分沿网络均匀分布。通过不同的表征技术(TGA、NMR 和 IR 光谱、化学和元素分析、TEM 和结构测量)对杂化材料进行了研究,验证了固体中不对称活性位点的稳定性和完整性。杂化材料 HybPyr 是一种优异的不对称多相且可回收的催化剂,用于线性醛与 β-硝基苯乙烯衍生物的对映选择性迈克尔加成反应,并对反应产物具有高度立体控制。