4170-71-2Relevant articles and documents
Synthesis of allenylzinc reagents by 1,2-rearrangement of alkynyl(disilyl)zincates derived from acetylenic epoxides and acetylenic aziridines
Bochatay, Valentin N.,Debien, Laurent,Chemla, Fabrice,Ferreira, Franck,Jackowski, Olivier,Perez-Luna, Alejandro
, p. 609 - 616 (2017)
Lithium alkynyl(disilyl)zincates obtained from metalated ethynyloxiranes, as well as from N-tert-butanesulfinyl(ethynyl)aziridines or N-tert-butanesulfonyl(ethynyl)aziridines, undergo 1,2-migration of the organosilyl group with ring opening of the oxirane or aziridine ring by SNi displacement. A developed protocol that involves nBuLi for the metalation step offers a straightforward approach to the corresponding δ-oxy- and δ-amino α-silyl allenylzinc intermediates. The reagents derived from the epoxides are amenable to subsequent in situ condensation with aldehydes or ketones to provide 1,3-diols but not those derived from aziridines that only react sluggishly in similar condensations.
Electroorganic Reactions on Organic Electrodes. 6. Electrochemical Asymmetric Oxidation of Unsymmetric Sulfides to the Corresponding Chiral Sulfoxides on Poly(amino acid)-Coated Electrodes
Komori, Tetsuo,Nonaka, Tsutomu
, p. 2656 - 2659 (1984)
Alkyl aryl sulfides (1a-g) were electrochemically oxidized to the corresponding chiral sulfoxides (2a-g) (eq 1) by using poly(amino acid)-coated electrodes.The highest optical yield was 93percent, which was obtained in the oxidation of tert-butyl phenyl s
Chiral Br?nsted-Acid-Catalyzed Asymmetric Oxidation of Sulfenamide by Using H2O2: A Versatile Access to Sulfinamide and Sulfoxide with High Enantioselectivity
Ma, Long-Jun,Chen, Shu-Sen,Li, Guang-Xun,Zhu, Jin,Wang, Qi-Wei,Tang, Zhuo
, p. 1525 - 1530 (2019/02/01)
Herein, we describe an example of catalytic asymmetric synthesis of sulfinamides. Aromatic sulfenamides were chosen as useful substrates, because of the indispensable N-H bond, which could form an efficient hydrogen bond with chiral phosphoric acid. Hsub
Acid-Catalyzed Synthesis of Aryl[4,5]isothiazoles through a Sulfenic Acid Pathway
Sun, Zhihua,Yuan, Hong
supporting information, p. 1904 - 1908 (2019/09/30)
A new method to efficiently prepare 3-substituted aryl[4,5]isothiazoles by simply heating the starting materials with a catalytic amount of p -toluenesulfonic acid in toluene is reported. This simple procedure is well suitable for a variety of substrates
Stereoselective synthesis of isoindolinones and tert-butyl sulfoxides
Kaw?cki, Robert,Stańczyk, Wojciech,Jaglińska, Agnieszka
, p. 578 - 584 (2017/12/28)
A reaction of Grignard reagents with an optically pure N-sulfinylimine derived from methyl 2-formylbenzoate yields enantioenriched isoindolinones and tert-butyl sulfoxides. The products are formed by the addition of the nucleophile to N-sulfinylimine followed by cyclization to form N-tert-butylsulfinylisoindolinone, which readily undergoes substitution with a second equivalent of Grignard reagent. The reaction can be carried out in dichloromethane at room temperature or at elevated temperatures without any loss of stereoselectivity. The use of nucleophiles other than Grignard reagents has also been investigated.
Thermolysis-Induced Two- or Multicomponent Tandem Reactions Involving Isocyanides and Sulfenic-Acid-Generating Sulfoxides: Access to Diverse Sulfur-Containing Functional Scaffolds
Wu, Shengfeng,Lei, Xiaofang,Fan, Erkang,Sun, Zhihua
supporting information, p. 522 - 525 (2018/02/10)
Direct reaction of isocyanides with some sulfenic-acid-generating sulfoxides led to the effective formation of the corresponding thiocarbamic acid S-esters in good to high yields. A multicomponent reaction involving isocyanide, sulfoxide, and a suitable nucleophile has also been developed, providing ready access to a diverse range of sulfur-containing compounds, including isothioureas, carbonimidothioic acid esters, and carboximidothioic acid esters.
Multivariate Metal-Organic Frameworks as Multifunctional Heterogeneous Asymmetric Catalysts for Sequential Reactions
Xia, Qingchun,Li, Zijian,Tan, Chunxia,Liu, Yan,Gong, Wei,Cui, Yong
supporting information, p. 8259 - 8266 (2017/06/28)
The search for versatile heterogeneous catalysts with multiple active sites for broad asymmetric transformations has long been of great interest, but it remains a formidable synthetic challenge. Here we demonstrate that multivariate metal-organic frameworks (MTV-MOFs) can be used as an excellent platform to engineer heterogeneous catalysts featuring multiple and cooperative active sites. An isostructural series of 2-fold interpenetrated MTV-MOFs that contain up to three different chiral metallosalen catalysts was constructed and used as efficient and recyclable heterogeneous catalysts for a variety of asymmetric sequential alkene epoxidation/epoxide ring-opening reactions. Interpenetration of the frameworks brings metallosalen units adjacent to each other, allowing cooperative activation, which results in improved efficiency and enantioselectivity over the sum of the individual parts. The fact that manipulation of molecular catalysts in MTV-MOFs can control the activities and selectivities would facilitate the design of novel multifunctional materials for enantioselective processes.
Efficient Metal-Free Aerobic Photooxidation of Sulfides to Sulfoxides Mediated by a Vitamin B2Derivative and Visible Light
Nevesely, Tomá?,Svobodová, Eva,Chudoba, Josef,Sikorski, Marek,Cibulka, Radek
, p. 1654 - 1663 (2016/10/13)
We have developed a metal-free process for the aerobic photooxygenation of sulfides to sulfoxides mediated by riboflavin tetraacetate or riboflavin (vitamin B2) photocatalysts and visible light (450 nm) in an acetonitrile-water (85:15 v/v) mixture. The optimised solvent system leads to both singlet-oxygen and electron-transfer pathways in photooxygenation, thus allowing oxidation of electron-poor and electron-rich thioanisoles, dialkyl sulfides and sterically hindered sulfides. Besides having a broad substrate scope, the method has very short reaction times and requires low catalyst loading (down to 0.1 mol%). These properties are due to the high photocatalyst stability and the extremely high quantum yields (1.3 for thioanisole oxygenation). Moreover, the method is chemoselective, producing only sulfoxides without overoxidation to sulfones. Taking into account the broad substrate scope, high selectivity and high efficiency, this method distinguishes itself from those previously reported. Other advantages include easy work-up of the reaction mixture, the availability and biodegradability of the photocatalysts and mild reaction conditions. We demonstrated, on a preparative scale, its practical application in the synthesis of the psychostimulant modafinil, in the selective oxidation of methionine derivatives, and in the detoxification of mustard gas. (Figure presented.).
Synthesis of 3-Substituted Aryl[4,5]isothiazoles through an All-Heteroatom Wittig-Equivalent Process
Xu, Fanghui,Chen, Yuan,Fan, Erkang,Sun, Zhihua
supporting information, p. 2777 - 2779 (2016/06/15)
Extending the previous use of tert-butyl sulfoxide as the sulfinyl source, intramolecular sulfinylation of sulfonamides was successfully performed. The resulting sulfinimides were not isolated and instead were believed to go through an all-heteroatom Witt
Electron-deficient heteroarenium salts: An organocatalytic tool for activation of hydrogen peroxide in oxidations
?turala, Ji?í,Bohá?ová, Soňa,Chudoba, Josef,Metelková, Radka,Cibulka, Radek
, p. 2676 - 2699 (2015/03/18)
A series of monosubstituted pyrimidinium and pyrazinium triflates and 3,5-disubstituted pyridinium triflates were prepared and tested as simple catalysts of oxidations with hydrogen peroxide, using sulfoxidation as a model reaction. Their catalytic efficiency strongly depends on the type of substituent and is remarkable for derivatives with an electron-withdrawing group, showing reactivity comparable to that of flavinium salts which are the prominent organocatalysts for oxygenations. Because of their high stability and good accessibility, 4-(trifluoromethyl)pyrimidinium and 3,5-dinitropyridinium triflates are the catalysts of choice and were shown to catalyze oxidation of aliphatic and aromatic sulfides to sulfoxides, giving quantitative conversions, high preparative yields and excellent chemoselectivity. The high efficiency of electron-poor heteroarenium salts is rationalized by their ability to readily form adducts with nucleophiles, as documented by low pKR+ values (pKR+ red > -0.5 V). Hydrogen peroxide adducts formed in situ during catalytic oxidation act as substrate oxidizing agents. The Gibbs free energies of oxygen transfer from these heterocyclic hydroperoxides to thioanisole, obtained by calculations at the B3LYP/6-311++g(d,p) level, showed that they are much stronger oxidizing agents than alkyl hydroperoxides and in some cases are almost comparable to derivatives of flavin hydroperoxide acting as oxidizing agents in monooxygenases.
