Oxidative rearrangements of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol: a general, regiospecific synthesis of α-aryl ketones
作者:Michael W. Justik、Gerald F. Koser
DOI:10.1016/j.tetlet.2004.06.029
日期:2004.8
The treatment of arylalkenes with [hydroxy(tosyloxy)iodo]benzene in 95% methanol affords the corresponding α-aryl ketones. This oxidative rearrangement is general for acyclic and cyclic arylalkenes and permits regioselective syntheses of isomeric α-phenyl ketone pairs.
Bidentate Hydroxyalkyl NHC Ligands for the Copper-Catalyzed Asymmetric Allylic Substitution of Allyl Phosphates with Grignard Reagents
作者:Magaly Magrez、Yann Le Guen、Olivier Baslé、Christophe Crévisy、Marc Mauduit
DOI:10.1002/chem.201203969
日期:2013.1.21
Demonstrating their potential: Bidentate alkoxy NHC ligands have been used in the copper‐catalyzed asymmetricallylic alkylation of allylphosphates with Grignard reagents (see scheme). The method provides access to tertiary and quaternary chiral centers with high regio‐ and enantioselectivity. The system is also applied to the synthesis of chiral E,E‐dienes, a key structural motif prevalent in natural
A stereoselectivehypervalent iodine-promoted oxidative rearrangement of 1,1-disubstituted alkenes has been developed. This practically simple protocol provides access to enantioenriched α-arylated ketones without the use of transition metals from readily accessible alkenes.
β- and γ-Disubstituted Olefins: Substrates for Copper-Catalyzed Asymmetric Allylic Substitution
作者:Caroline A. Falciola、Karine Tissot-Croset、Hugo Reyneri、Alexandre Alexakis
DOI:10.1002/adsc.200800086
日期:2008.5.5
The copper-catalyzed asymmetric allylic alkylation has shown through many examples that it is a powerful means to generate stereogenic centers with mono β- and γ-substituted olefinic substrates. However, little has been reported about more substituted olefinic patterns, such as β-disubstituted allylic electrophiles. In this paper, we show that a simple procedure using easily accessible Grignard reagents
SmI2-mediated reductive cleavage of α-hetero substituents of α-alkyl or α-aryl ketones and lactone gave the corresponding “thermodynamic samarium enolates”. Enantioselective protonation of the samarium enolates with C2-symmetric chiral diols afforded the corresponding ketones and lactone in moderate to high enantioselectivities.