由TiO 2和酚类形成的表面电荷转移复合物在可见光光催化中显示出巨大的潜力。然而,背电子转移限制了电荷转移效率和表面络合物中酚类的活化。在此,我们揭示了通过引入碱来有效活化表面复合物中的酚类。同源偶联反应和丁基化羟基甲苯捕获的实验都清楚地证明了从各种木质素衍生的底物中产生酚自由基。碱的加入引起了表面配合物的蓝移吸收,同时增加了可见光诱导的从衬底到TiO 2的电子激发。振动光谱表明酚盐和 TiO 2之间的相互作用更强高于中性苯酚。这种碱基触发策略可能有助于通过表面复合物对酚进行有用的转化或降解。
Phenols are transformed into nitrophenols by the combined action of ozonized oxygen and nitrogen dioxide (Kyodai nitration) in different solvents. Dipolemoments of the solvents were correlated with the ortho/para nitration ratio with phenol, showing an influence of the polarity of the solvent on the ortho/para nitration selectivity. A Hammett ρ of −0.72 was obtained in the Kyodai nitration of 4-substituted
The evaluation of a biogenetically based approach to the synthesis of octahydro-1h-benzofuro[3,2-e]isoquinolines
作者:J.F. Ajao、C.W. Bird、Y.-P. Chauhan
DOI:10.1016/s0040-4020(01)96538-x
日期:1985.1
derivatives by intermolecular oxidative phenolic coupling has been studied. A variety of successful coupling reactions have been effected between2-naphthol or 4-t-butylphenol and p-cresol, 2-(p-hydroxyphenyl)ethanol, 3,4-dimethylphenol, 5-indanol and 6-hydroxytetralin, but 2-acetyl-7-hydroxytetrahydroisoquinoline failed to participate in such reactions.
Efficient oxidative ipso-fluorination of para-substituted phenols using pyridinium polyhydrogen fluoride in combination with hypervalent iodine(III) reagents
4-fluorocyclohexa-2,5-dienones in a good yield. (R,S)-1,1′-Bi-5,6,7,8-tetrahydro-2-naphthol (and its monoacetate) yields atropoisomericfluorocyclohexadienones. The 4-substituted carbamate open-chain phenols were readily converted to fluorohydroindolenone and fluorohydroquinolenone derivatives by intramolecular conjugate addition.
Nucleophilic para-fluorination of 4-alkylphenols by hypervalent iodine reagent and pyridinium polyhydrogen fluoride (PPHF) a novel route to 4-fluorocyclohexa-2,5-dienones
Ipso-fluorination of 4-alkylphenols with C6H5-I(OCOCF3)2-pyridinium polyhydrogenfluoride (PPHF) yields 4—fluorocyclohexa-2,5-dienones.
用C 6 H 5 -I(OCOCF 3)2-吡啶鎓多氟化氢(PPHF)对4-烷基苯酚进行异氟氟化,生成4-氟环己-2,5-二壬烯。
Development of the radical C–O coupling reaction of phenols toward the synthesis of natural products comprising a diaryl ether skeleton
作者:Kumpei Tanaka、Hiroaki Gotoh
DOI:10.1016/j.tet.2019.05.035
日期:2019.7
atom of phenols. In this study, various radical-generating reagents and conditions were investigated with the aim of developing a short-step construction method of the diaryl ether skeleton by the radical homo-coupling of two phenol molecules. In addition, cross-coupling reactions between radicals of 2,4,6-tri-tert-butylphenol and p-substituted phenol were conducted to synthesize eight C (ortho)–O coupling