57197-11-2Relevant academic research and scientific papers
Coupling of Quinone Monoacetals with Vinyl Ethers Effected by Tetrabutylammonium Triflate: Regiocontrolled Synthesis of 2-Oxygenated Dihydrobenzofurans
Kamitanaka, Tohru,Tsunoda, Yusuke,Fujita, Yuriko,Dohi, Toshifumi,Kita, Yasuyuki
supporting information, p. 9025 - 9029 (2021/11/24)
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 triflate anion catalyst for stabilization of the highly reactive cationic intermediate.
Synthetic Studies of the Rubellin Natural Products: Development of a Stereoselective Strategy and Total Synthesis of (+)-Rubellin C
Gartman, Jackson A.,Tambar, Uttam K.
, p. 11237 - 11262 (2021/08/16)
This manuscript describes our studies of the class of natural products known as the rubellins, culminating in the total synthesis of (+)-rubellin C. These anthraquinone-based natural products contain a variety of stereochemical and architectural motifs, including a 6-5-6-fused ring system, 5 stereogenic centers, and a central quaternary center. Herein, we report our development of a strategy to target the stereochemically dense core and anthraquinone nucleus, including approaches such as a bifunctional allylboron and vinyl triflate reagent, an anthraquinone benzylic metalation strategy, and a late-stage anthraquinone introduction strategy. Our studies culminate in a successful route to highly functionalized anthraquinone-based natural product scaffolds and a stereoselective total synthesis of (+)-rubellin C. These strategies and outcomes will aid in synthetic planning toward anthraquinone-based natural products of high interest.
Lewis Acid-Mediated Site-Selective Synthesis of Oxygenated Biaryls from Methoxyphenols and Electron-Rich Arenes
Sharma, Shivangi,Parumala, Santosh Kumar Reddy,Peddinti, Rama Krishna
, p. 9367 - 9383 (2017/09/22)
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 generated masked benzoquinones.
Direct synthesis of anilines and nitrosobenzenes from phenols
St Amant,Frazier,Newmeyer,Fruehauf,Read De Alaniz
supporting information, p. 5520 - 5524 (2016/07/06)
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.
Double hetero-Michael addition of N -substituted hydroxylamines to quinone monoketals: Synthesis of bridged isoxazolidines
Yin, Zhiwei,Zhang, Jinzhu,Wu, Jing,Liu, Che,Sioson, Kate,Devany, Matthew,Hu, Chunhua,Zheng, Shengping
supporting information, p. 3534 - 3537 (2013/08/23)
A general synthesis of bridged isoxazolidines from a double hetero-Michael addition of N-substituted hydroxylamines to quinone monoketals has been developed. The different addition order of N-benzylhydroxylamine and N-Boc hydroxylamine is also discussed.
Tin tetrachloride-catalyzed regiospecific allylic substitution of quinone monoketals: An easy entry to benzofurans and coumestans
Liu, Yingjie,Liu, Jingxin,Wang, Mang,Liu, Jun,Liu, Qun
supporting information, p. 2678 - 2682 (2013/01/15)
A highly regioselective allylic substitution of quinone monoketals with a-oxoketene dithioacetals is achieved under the catalysis of only tin tetrachloride (1 mol%). The advantages of the reaction, including its simplicity, rapidity, low catalyst loading of inexpensive tin tetrachloride, mild conditions and; in particular, the regiospecificity, is proposed to be due to a pseudo-intramolecular process. This new synthetic method provides a facile [3+2] cycloaddition route to benzofurans and is highlighted by the synthesis of coumestans.
Hypervalent iodine mediated synthesis of carbamate protected p-quinone monoimine ketals and p-benzoquinone monoketals
Bodipati, Naganjaneyulu,Peddinti, Rama Krishna
experimental part, p. 4549 - 4553 (2012/07/14)
A simple and efficient method for the synthesis of p-quinone monoimide ketals and p-benzoquinone monoketals by using a hypervalent iodine reagent, diacetoxyiodobenzene, has been developed. These two types of ketals are achieved from a single starting material by varying the reaction conditions.
A direct route to fluostatin C by a fascinating Diels-Alder reaction
Yu, Maolin,Danishefsky, Samuel J.
, p. 2783 - 2785 (2008/09/20)
The Diels-Alder reactions between vinylindenes (5 or 6) as the dienes with quinoneketals (7 or 8) or with methacrolein as the dienophiles were investigated. The remarkable regioselectivities of these Diels-Alder adducts suggested that the regiopreferences of these dienes and dienophiles in these cases are not a fixed property of each component of the cycloaddition but are mutually contigent. This paper shows how the Diels-Alder reaction between 6 and 8 was applied to the inaugural total syntheses of fluostatin C and E. Copyright
Synthesis of polysubstituted bicyclo[3.3.1]nonane-3,7-diones from cyclohexa-2,5-dienones and dimethyl 1,3-acetonedicarboxylate
Camps, Pelayo,González, Albert,Mu?oz-Torrero, Diego,Simon, Montserrat,Zú?iga, Adriana,Martins, Miriam A.,Font-Bardia, Mercè,Solans, Xavier
, p. 8141 - 8151 (2007/10/03)
Oxidation of polysubstituted phenols with phenyliodonium diacetate gives cyclohexa-2,5-dienones, which on reaction with dimethyl 1,3-acetonedicarboxylate afford double-Michael-addition derivatives, whose hydrolysis and decarboxylation provides polysubstituted bicyclo[3.3.1]nonane-3,7-diones. For steric and/or electronic reasons, the Michael reaction only works with 3,5-unsubstituted or 3-substituted cyclohexa-2,5-dienones, if the substituent is not an electron-releasing or a good electron-withdrawing group. Hydrolysis and decarboxylation of the double-Michael adducts from 2,4,4- or 2,4,4,6-substituted cyclohexa-2,5-dienones gives only products of partial hydrolysis and decarboxylation, which exist exclusively in the enol form. (C) 2000 Elsevier Science Ltd.
Chemistry of Quinone Derivatives. Quinone Monoketals via Hydrolysis of Electrochemically Derived Quinone Bisketals
Henton, Daniel R.,Anderson, Keith,Manning, Michael J.,Swenton, John S.
, p. 3422 - 3433 (2007/10/02)
The monohydrolysis of nine naphthoquinone bisketals and nine benzoquinone bisketals has been studied.In the acetamido, bromo, methyl, methoxy, and thiomethyl monosubstituted compounds, hydrolysis occurs at the ketal more distant from the substituent.The regiochemistry is nearly exclusive in the naphthoquinone series and is highly selective in the benzoquinone series.For disubstituted benzoquinone and naphthoquinone bisketals, the monohydrolysis is often regiospecific but substituent dependent.The origin of the regioselectivity in the reactions is briefly discussed.
