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
Asymmetric Michael addition of aldehydes to nitroalkenes using a primary amino acid lithium salt
作者:Masanori Yoshida、Atsushi Sato、Shoji Hara
DOI:10.1039/c003940c
日期:——
Enantioselective Michaeladdition of aldehydes to nitroalkenes was successfully carried out by asymmetric catalysis with L-phenylalanine lithium salt, giving γ-nitroaldehydes in good yields with high enantioselectivity.
Michaeladditions of different aldehydes and ketones to β-nitrostyrene and 2-(β-nitrovinyl)thiophene in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) were studied. β-Nitrostyrene was a better acceptor than 2-(β-nitrovinyl)thiophene, in terms of both reactivity and selectivity. Aldehydes proved to be better donors than ketones, which were themselves better than β-diketones. L-proline proved
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