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
Efficient Synthesis of Oxygenated Terphenyls and Other Oligomers: Sequential Arylation Reactions Through Phenol Oxidation-Rearomatization
作者:Toshifumi Dohi、Tohru Kamitanaka、Shohei Watanabe、Yinjun Hu、Naohiko Washimi、Yasuyuki Kita
DOI:10.1002/chem.201202086
日期:2012.10.22
One by one: Starting from simple phenols, a diverse series of oxygenatedterphenyl compounds can be prepared in a concise and practical manner using sequentialarylationreactions involving phenol oxidation/rearomatization and quinone monoacetal intermediates (see scheme). Many of the terphenyl products can be used for preparing well‐defined oligomers and, furthermore, contain valuable functional groups
[3 + 2] Coupling of Quinone Monoacetals with Vinyl Ethers Effected by Tetrabutylammonium Triflate: Regiocontrolled Synthesis of 2-Oxygenated Dihydrobenzofurans
作者:Tohru Kamitanaka、Yusuke Tsunoda、Yuriko Fujita、Toshifumi Dohi、Yasuyuki Kita
DOI:10.1021/acs.orglett.1c02792
日期:2021.12.3
The synthesis of 2-oxygenated dihydrobenzofurans involving the [3 + 2] coupling of quinone monoacetals with vinyl ethers has been realized by tetrabutylammonium triflate catalysis. The reaction involves a new activation method of the acetal moiety in quinone monoacetals under acid-free conditions affording the highly oxygenated dihydrobenzofurans. This new activation mode was achieved by using the