Enantioselective Addition of Nitromethane to 2-Acylpyridine N-Oxides. Expanding the Generation of Quaternary Stereocenters with the Henry Reaction
摘要:
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.
CYCLOALKYLOXY-AND HETEROCYCLOALKYLOXYPYRIDINE COMPOUNDS AS MODULATORS OF THE HISTAMINE H3 RECEPTOR
申请人:Letavic Michael A.
公开号:US20090131415A1
公开(公告)日:2009-05-21
Certain cycloalkyloxy- and heterocycloalkyloxypyridine compounds are histamine H
3
receptor modulators useful in the treatment of histamine H
3
receptor-mediated diseases.
catalytic asymmetric Henry reaction of α-keto esters, 2-acylpyridines and 2-acylpyridine N-oxides. The corresponding β-nitro-α-hydroxy esters were obtained in good to excellent yields (up to 99%) with a high enantiomeric excess (ee) (up to 94%) with a catalyst loading of 1–2 mol%. The desired products of 2-acylpyridines and 2-acylpyridine N-oxides, which were simple methyl ketones, were obtained in medium
A Cu-BOX catalysed enantioselective Mukaiyama-aldol reaction with difluorinated silyl enol ethers and acylpyridine <i>N</i>-oxides
作者:Amparo Sanz-Marco、Daniel Esperilla、Marc Montesinos-Magraner、Carlos Vila、M. Carmen Muñoz、José R. Pedro、Gonzalo Blay
DOI:10.1039/d2ob01763f
日期:——
A Cu(II)/BOX complexcatalyses the enantioselective addition of difluorinated silyl enol ethers to acylpyridine N-oxides. The reaction provides difluorinated chiral tertiary alcohols of great interest in medicinal chemistry. These compounds are obtained in moderate to excellent yields and with high enantioselectivities. The stereochemical outcome of the reaction has been explained by DFT calculations
Cu( II )/BOX 络合物催化二氟化甲硅烷基烯醇醚对映选择性加成酰基吡啶N-氧化物。该反应提供了在药物化学中具有重要意义的二氟化手性叔醇。这些化合物以中等到极好的产率和高对映体选择性获得。反应的立体化学结果已通过 DFT 计算得到解释。