Coupling of Quinone Monoacetals Promoted by Sandwiched Brønsted Acids: Synthesis of Oxygenated Biaryls
作者:Toshifumi Dohi、Naohiko Washimi、Tohru Kamitanaka、Kei-ichiro Fukushima、Yasuyuki Kita
DOI:10.1002/anie.201101646
日期:2011.6.27
Unusual protons: Brønsted acids sandwiched between sheets of solid acids, such as montmorillonites, activated quinone monoacetals 1 to selectively react with aromatic nucleophiles 2 in an unprecedented substitution reaction. The syntheticutility of the strategy for obtaining highly oxygenated biaryls 3 is highlighted by the synthesis of gilvocarcin aglycones.
A rapid, efficient, and metal-free Lewis acid-mediated methodology has been developed for the site-selective synthesis of unsymmetrical oxygenated biaryls. This simple and efficient methodology furnished highly oxygenated and functionalized unsymmetrical biaryls in good to excellent yields by the direct oxidative coupling of electron-rich arenes to the α-position of carbonyl functionality of in situ
Sulfoxide-mediated oxidative cross-coupling of phenols
作者:Zhen He、Gregory J. P. Perry、David J. Procter
DOI:10.1039/c9sc05668h
日期:——
A metal-free, oxidative coupling of phenols with various nucleophiles, including arenes, 1,3-diketones and other phenols, is reported. Cross-coupling is mediated by a sulfoxide which inverts the reactivity of the phenol partner. Crucially, the process shows high selectivity for cross-versus homo-coupling and allows efficient access to a variety of aromatic scaffolds including biaryls, benzofurans and
Dynamic kinetic resolution of biaryl atropisomers by chiral dialkylaminopyridine catalysts
作者:Gaoyuan Ma、Chao Deng、Jun Deng、Mukund P. Sibi
DOI:10.1039/c8ob00384j
日期:——
The acylative dynamic kineticresolution (DKR) of configurationally unstable biaryl atropisomers is achieved by using newly developed chiral dialkylaminopyridine catalysts with fluxional chirality. Various types of biaryl substrates containing phenolic structures were subjected to the DKR to obtain a range of acylated biaryl products with enantiomeric ratios up to 90 : 10.