Synthesis of Acid-ResistantP-Quinone Monoketals and Thermally Stable 4,4-Dialkoxycyclohexa-2,5-Dien-1-OLS
摘要:
Preparation and high resistance to acid hydrolysis of sterically hindered p-quinone monoketals 1a, 1b and 1c are described. Thermal stability of ketal alcohols 2a and 2b derived from 1a and 1c, respectively, is also mentioned.
disclose a scalable organocatalytic direct arylation approach for the regio- and atroposelective synthesis of non-C2-symmetric 2,2'-dihydroxy-1,1'-binaphthalenes (BINOLs). In the presence of catalytic amounts of axially chiral phosphoric acids, phenols and naphthols are coupled with iminoquinones via a cascade process that involves sequential aminal formation, sigmatropic rearrangement, and rearomatization
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.
Direct synthesis of anilines and nitrosobenzenes from phenols
作者:A. H. St. Amant、C. P. Frazier、B. Newmeyer、K. R. Fruehauf、J. Read de Alaniz
DOI:10.1039/c6ob00073h
日期:——
A one-pot synthesis of anilines and nitrosobenzenes from phenols has been developed using an ipso-oxidative aromatic substitution (iSOAr) process. The products are obtained in good yields under mild and metal-free conditions. The leaving group effect on reactions that proceed through mixed quionone monoketals has also been investigated and a predictive model has been established.
已经使用ipso-氧化性芳族取代(i S O Ar)方法开发了一种从苯酚一锅合成苯胺和亚硝基苯的方法。在温和且不含金属的条件下,可以以高收率获得产品。还研究了离去基团对通过混合的醌酮单缩酮进行的反应的影响,并建立了预测模型。
Brønsted Acid-Controlled [3 + 2] Coupling Reaction of Quinone Monoacetals with Alkene Nucleophiles: A Catalytic System of Perfluorinated Acids and Hydrogen Bond Donor for the Construction of Benzofurans
作者:Yinjun Hu、Tohru Kamitanaka、Yusuke Mishima、Toshifumi Dohi、Yasuyuki Kita
DOI:10.1021/jo400613z
日期:2013.6.7
We have developed an efficient Brønsted acid-controlled strategy for the [3 + 2] coupling reaction of quinonemonoacetals (QMAs) with nucleophilic alkenes, which is triggered by the particular use of a specific acid promoter, perfluorinated acid, and a solvent, fluoroalcohol. This new coupling reaction smoothly proceeded with high regiospecificity in regard with QMAs for introducing π-nucleophiles
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