Ruthenium-Catalyzed Aminomethylation and Methylation of Phenol Derivatives Utilizing Methanol as the C<sub>1</sub>Source
作者:Seoksun Kim、Soon Hyeok Hong
DOI:10.1002/adsc.201601117
日期:2017.3.6
involving ortho‐aminomethylation of phenol was developed via ruthenium‐catalyzed dehydrogenation of methanol, an environmentally benign C1 building block, without the use of reactive reagents. The reaction was successfully applied to a range of substrates. When naphthol was employed instead of phenol, only methylation was observed. On the basis of various mechanistic studies, we propose that formamide barely
A New Synthesis of<i>o</i>-Quinonemethides and Their Inter- and Intramolecular Cyclization Reactions
作者:Tsutomu Inoue、Seiichi Inoue、Kikumasa Sato
DOI:10.1246/bcsj.63.1062
日期:1990.4
The reaction of o-[1-(alkylthio)alkyl]phenols with silver(I) oxide at room temperature generated o-quinonemethides in good yields along with silver alkanethiolate. This mechanism, based upon one-electron oxidation, is excluded in view of several experimental facts. The resulting o-quinonemethides reacted efficiently with ethyl vinyl ether to afford cis-chromans as the result of endo cycloaddition between (E)-o-quinonemethides and the ether. Similarly, o-[1-(alkylthio)allyl]phenols were converted to cis-chromans via the corresponding (E)-o-quinonemethides (6-allylidenecyclohexadienone). In the absence of dienophiles, some chromenes were obtained from the allylphenols.
Mild and Rapid Method for the Generation of <i>ortho</i>-(Naphtho)quinone Methide Intermediates
作者:Abdul kadar Shaikh、Alexander J. A. Cobb、George Varvounis
DOI:10.1021/ol203196n
日期:2012.1.20
A new mild method has been devised for generating o-(naphtho)quinonemethidesvia fluoride-induced desilylation of silyl derivatives of o-hydroxybenzyl(or 1-naphthylmethyl) nitrate. The reactive o-(naphtho)quinonemethideintermediates were trapped by C, O, N, and S nucleophiles and underwent “inverse electron-demand” hetero-Diels–Alder reaction with dienophiles to give stable adducts. The method has
Generation and hetero-Diels–Alder reactions of an o-quinone methide under mild, anionic conditions: rapid synthesis of mono-benzannelated spiroketals
作者:Christopher D. Bray
DOI:10.1039/b806593d
日期:——
Deprotonation of o-hydroxybenzyl acetate with (i)PrMgCl provides a method of generating an o-quinonemethide under mild, anionic conditions, such that highly sensitive exo-enol ethers can be employed as 2pi partners in hetero-Diels-Alder reactions. This process results in mono-benzannelated spiroketals such as those found in the natural products berkelic acid, the chaetoquadrins or cephalostatin 6
Substituent Effects on Oxidation-Induced Formation of Quinone Methides from Arylboronic Ester Precursors
作者:Sheng Cao、Robin Christiansen、Xiaohua Peng
DOI:10.1002/chem.201300539
日期:2013.7.1
efficiently generate QMs under physiological conditions. Finally, a quantitative relationship between the structure and activity has been established for the arylboronicesters by using a Hammett plot. The reactivity of the arylboronic acids/esters and the inhibition or facilitation of QM formation can now be predictably adjusted. This adjustment is important as some applications may benefit and others
一系列含有不同芳族取代基和各种苄基离去基团(BR或N-芳基硼酸酯的+我3溴- )已被合成。已经研究了取代基对其与H 2 O 2的反应性和甲基化醌(QM)形成的影响。NMR光谱和乙基乙烯基醚(EVE)捕获实验分别用于确定反应机理和QM形成。在硼酸酯的氧化裂解过程中不会产生QM,而是在生理条件下通过苯酚产物的后续转化产生的。吸电子取代基(例如芳族F,NO 2或苄基N )促进了氧化脱硼+我3溴- ,而给电子取代基或更好的离去基团有利于QM产生。包含芳香族CH 3或OMe基团或良好离去基团(Br)的化合物可在生理条件下有效产生QM。最后,通过使用哈米特图建立了芳基硼酸酯的结构与活性之间的定量关系。现在可以预测地调整芳基硼酸/酯的反应性以及抑制或促进QM的形成。此调整很重要,因为某些应用程序可能会受益,而其他应用程序可能会受到QM生成的限制。