Ruthenium‐Catalyzed Oxidative Dearomatization of Phenols to 4‐(tert‐Butylperoxy)cyclohexadienones: Synthesis of 2‐Substituted Quinones from p‐Substituted Phenols

Abstract

The ruthenium-catalyzed oxidation of phenols with tert-butyl hydroperoxide efficiently gives the corresponding 4-(tert-butylperoxy)cyclohexadienones. The oxidation proceeds selectively because of ruthenium's ability for rapid single-electron transfer. This biomimetic oxidation reaction is highly useful to obtain the metabolic compounds desired for confirming the safety of medicines and related compounds. Typically, the first metabolic compound of the female hormone estrone is readily obtained by this biomimetic oxidation reaction. The resulting 4-(tert-butylperoxy)cyclohexadienones are versatile synthetic intermediates, which can be transformed into

The evaluation of 1,4-benzoquinones as inhibitors of human monoamine oxidase

“…mp 43-44 °C[52] 1. H NMR (600 35.2, 127.0, 128.8, 129.3, 133.2, 136.3, 136.6, 148.7, 187.2, 187.7; APCI-HRMS m/z: calcd for C 13 H 10 O 2 (M + ), 198.0681, found 198.0688; purity (HPLC): 99.0%.…”

Catalytic Electrophilic Alkylation of p‐Quinones through a Redox Chain Reaction

“…When the electronic effects of benzyl esters are differentiated by amethoxy group,only the one that takes the para position of the methoxy is reactive (7). Finally,anethyl ester of asthma drug Seratrodast [12] was synthesized (8), thus demonstrating the potential of this method in pharmaceutical synthesis.…”

“…[4] Thee lectronic properties of quinone derivatives have also attracted much attention from researchers working on functional materials. [5] Theb ulk of established chemical syntheses of quinones use af unctionalization-oxidation strategy.S ubstituents are first installed on hydroquinones,p henols,o rp henyl ethers through Friedel-Crafts reactions, [6] radical reactions, [7] and transition-metal-catalyzed coupling reactions, [8] and the resulting compounds are then oxidized to quinones. [9] Functionalized hydroquinone precursors can also be obtained through nucleophilic addition [10] and cycloaddition reaction [11] of simple quinones to substituted 2-cyclohexen-1,4-dione intermediates,w hich can then rearrange to hydroquinone and be oxidized.…”

Catalytic Electrophilic Alkylation of p‐Quinones through a Redox Chain Reaction

“…initiator,t he reaction between 2-cyclohexenyl acetate (1b) and 2,3-dimethylbenzoquinone (2c)g enerates a6 0:40 mixture of the alkylation product 3bc and the cycloaddition product 4bc.T he reaction may first generate 4bc,which may then initiate the redox-chain pathway to 3bc.I nc ontrast, adding merely af ew mol %o f2 ,3-dimethylhydroquinone in the beginning improved the selectivity to 93:7. Finally,anethyl ester of asthma drug Seratrodast [12] was synthesized (8), thus demonstrating the potential of this method in pharmaceutical synthesis. However,a dding too much hydroquinone did not proportionally improve the reaction yield and selectivity.Infact, the reaction between pure hydroquinone and prenyl ester does not work very well in the working solvent dichloromethane, likely due to the poor solubility of hydroquinone.…”

“…[3] Many natural or synthetic quinone compounds thus exhibit potent biological activities as drug candidates for targeting relevant biochemical processes. [5] Theb ulk of established chemical syntheses of quinones use af unctionalization-oxidation strategy.S ubstituents are first installed on hydroquinones,p henols,o rp henyl ethers through Friedel-Crafts reactions, [6] radical reactions, [7] and transition-metal-catalyzed coupling reactions, [8] and the resulting compounds are then oxidized to quinones. [5] Theb ulk of established chemical syntheses of quinones use af unctionalization-oxidation strategy.S ubstituents are first installed on hydroquinones,p henols,o rp henyl ethers through Friedel-Crafts reactions, [6] radical reactions, [7] and transition-metal-catalyzed coupling reactions, [8] and the resulting compounds are then oxidized to quinones.…”