A novelbifunctional organocatalyst library combining both aminocatalysis and phosphonicacid activation was used for the first time as an efficient tool for the stereoselectiveMichaeladdition of aldehydes with several aromatic nitroalkenes with good selectivities up to 95:5 dr and 93:7 er. Due to their high water solubility, the catalysts were easilyrecyclable and could be reused over several cycles
One-pot asymmetric synthesis of γ-nitroaldehydes from aldehydes and nitroalkanes was achieved by a catalytic tandem reaction using a primary amino acid lithium salt, O-tert-butyldiphenylsilyl l-tyrosine lithium salt, as a catalyst. Various aryl, alkenyl, and alkyl aldehydes were converted into γ-nitroaldehydes via in situ generation of nitroalkenes.
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
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