0000000000602164
AUTHOR
Melireth Holmquist
Highly enantioselective aza-Henry reaction with isatin N-Boc ketimines.
A highly enantioselective aza-Henry reaction with isatin N-Boc ketimines using a Cu(II)–BOX complex as a catalyst is described. The reaction, which does not require protection of the N1 atom, provides the corresponding nitroamines bearing a quaternary stereocentre with high yields and enantiomeric excesses (up to 99.9%).
ChemInform Abstract: Highly Enantioselective Aza-Henry Reaction with Isatin N-Boc Ketimines.
The asymmetric aza-Henry reaction of isatin N-Boc-ketimines (I) with nitromethane in the presence of a Cu-Ph-box complex leads to a series of N-Boc-protected nitroamines (III) with high enantioselectivity in most cases.
ChemInform Abstract: Aza-Henry Reaction of Isatin Ketimines with Methyl 4-Nitrobutyrate en Route to Spiro[piperidine-3,3′-oxindoles].
A new enantioselective route to spiro[piperidine-3,3′-oxindoles] from isatin ketimines is described. The aza-Henry reaction of N-Boc-isatin ketimines with methyl 4-nitrobutyrate in the presence of a Ph2BOX-CuBr2 complex provided the corresponding nitro amino esters with good diastereoselectivity and excellent enantioselectivity (up to >99% ee). The aza-Henry adducts were transformed into spiro[piperidine-3,3′-oxindoles] after reduction of the nitro group to oxime, and cleavage of the N-Boc group and lactamisation.
Aplicación de la topología molecular para la predicción de biodegradación anaerobia de clorofenoles
Se ha aplicado la topología molecular y el análisis de regresión multilineal en la búsqueda de un modelo de relación cuantitativa estructura-actividad (QSAR) capaz de predecir la capacidad de biodegradación anaerobia de un grupo de clorofenoles. Tomando el valor de la constante de velocidad de desaparición del derivado clorofenolico, log k, como variable dependiente y los descriptores topológicos como variables independientes, se obtuvo una ecuación con tres variables y coeficientes de correlación y de predicción , R2=0.9291 y Q2=0.870. El modelo fue validado a través de una validación interna y un test de aleatoriedad. Los resultados obtenidos muestran una alta capacidad de predicción para…
Enantioselective Addition of Nitromethane to 2-Acylpyridine N-Oxides. Expanding the Generation of Quaternary Stereocenters with the Henry Reaction
[EN] The direct asymmetric Henry reaction with prochiral ketones, leading to tertiary nitroaldols, is an elusive reaction so far limited to a reduced number of reactive substrates such as trifluoromethyl ketones or alpha-keto carbonyl compounds. Expanding the scope of this important reaction, the direct asymmetric addition of nitromethane to 2-acylpyridine N-oxides catalyzed by a BOX-Cu(II) complex to give the corresponding pyridine-derived tertiary nitroaldols having a quaternary stereogenic center with variable yields and good enantioselectivity, is described.
Aza-Henry Reaction of Isatin Ketimines with Methyl 4-Nitrobutyrate en Route to Spiro[piperidine-3,3′-oxindoles]
A new enantioselective route to spiro[piperidine-3,3′-oxindoles] from isatin ketimines is described. The aza-Henry reaction of N-Boc-isatin ketimines with methyl 4-nitrobutyrate in the presence of a Ph2BOX-CuBr2 complex provided the corresponding nitro amino esters with good diastereoselectivity and excellent enantioselectivity (up to >99% ee). The aza-Henry adducts were transformed into spiro[piperidine-3,3′-oxindoles] after reduction of the nitro group to oxime, and cleavage of the N-Boc group and lactamisation.
ChemInform Abstract: Enantioselective Addition of Nitromethane to 2-Acylpyridine N-Oxides. Expanding the Generation of Quaternary Stereocenters with the Henry Reaction.
The direct asymmetric Henry reaction with prochiral ketones, leading to tertiary nitroaldols, is an elusive reaction so far limited to a reduced number of reactive substrates such as trifluoromethyl ketones or α-keto carbonyl compounds. Expanding the scope of this important reaction, the direct asymmetric addition of nitromethane to 2-acylpyridine N-oxides catalyzed by a BOX-Cu(II) complex to give the corresponding pyridine-derived tertiary nitroaldols having a quaternary stereogenic center with variable yields and good enantioselectivity, is described.
CCDC 1415301: Experimental Crystal Structure Determination
Related Article: Melireth Holmquist, Gonzalo Blay , M. Carmen Muñoz and José R. Pedro|2015|Adv.Synth.Catal.|357|3857|doi:10.1002/adsc.201500716
CCDC 989964: Experimental Crystal Structure Determination
Related Article: Melireth Holmquist, Gonzalo Blay, M. Carmen Muñoz, and José R. Pedro|2014|Org.Lett.|16|1204|doi:10.1021/ol500082d