65251-10-7Relevant academic research and scientific papers
Access to Spirocyclic Benzothiophenones with Multiple Stereocenters via an Organocatalytic Cascade Reaction
Formánek, Bed?ich,Tauchman, Ji?í,Císa?ová, Ivana,Vesely, Jan
, p. 8510 - 8521 (2020/07/16)
The present report describes an organocatalytic cascade reaction between 2-alkylidene benzo[b]thiophenone derivatives and enones in the presence of the Cinchona alkaloid amine. Spirobenzothiophenonic cyclohexane derivatives containing three stereocenters were prepared via one-step synthesis in yields ranging from 88 to 96% and in enantioselectivities (enantiomeric excess (ee)) ranging from 85 to 97%, with diastereoselectivities of approximately 14/2/1. Therefore, this method provides an efficient route for the synthesis of a new class of optically active 2-spirobenzothiophenones.
Cu(I)/chiral bisoxazoline-catalyzed enantioselective sommelet-hauser rearrangement of sulfonium ylides
Wang, Jianbo,Li, Shu-Sen
supporting information, p. 12343 - 12358 (2020/11/10)
Catalytic asymmetric thia-Sommelet-Hauser rearrangement of sulfonium ylides remains a great challenge due to its multistep reaction mechanism involving metal carbene formation, proton transfer, and [2,3]-sigmatropic rearrangement. In particular, the key problem of such reactions is the differentiation of the enantiotopic lone pair electrons of sulfur, which generates the sulfonium ylide intermediate bearing chirality on the sulfur atom. With a modified chiral bisoxazoline ligand, we developed a Cu(I)- catalyzed asymmetric thia-Sommelet-Hauser rearrangement with good to excellent enantioselectivities. Mechanistic studies provide insights into the details of the reaction mechanism.
Sulfoxide Reduction/C(sp3)-S Metathesis Cascade in Ionic Liquid
Liu, Chenjing,Chen, Dengfeng,Fu, Yuanyuan,Wang, Fei,Luo, Jinyue,Huang, Shenlin
supporting information, p. 5701 - 5705 (2020/07/24)
A sulfoxide reduction/C-S bond metathesis cascade between sulfoxides and alkyl bromides has been developed to access high-value sulfides without the use of any catalysts or bases. In this cascade, classical Kornblum oxidation is employed to reduce sulfoxides with alkyl bromides in ionic liquid. This protocol features high functional tolerance, mild conditions, promising scalability, and sustainable solvents.
Asymmetric Catalytic [2,3] Stevens and Sommelet–Hauser Rearrangements of α-Diazo Pyrazoleamides with Sulfides
Lin, Xiaobin,Yang, Wei,Yang, Wenkun,Liu, Xiaohua,Feng, Xiaoming
supporting information, p. 13492 - 13498 (2019/08/28)
Catalytic enantioselective [2,3] Stevens and Sommelet–Hauser rearrangements of α-diazo pyrazoleamides with sulfides were achieved by utilizing chiral N,N′-dioxide/nickel(II) complex catalysts. These rearrangements proceeded well under mild reac
Sulfonium ylide formation and subsequent C[sbnd]S bond cleavage of aromatic isopropyl sulfide catalyzed by hemin in aqueous solvent
Yan, Xiaojing,Li, Chang,Xu, Xiaofei,He, Quan,Zhao, Xiaoyong,Pan, Yuanjiang
supporting information, p. 3081 - 3087 (2019/05/08)
Heme is an abundant and widely existed cofactor for a variety of metalloenzymes, whose broader use is generally impeded by its high instability and poor solubility. Here we report an environment-benign and efficient strategy for the sulfonium ylide formation and subsequent C[sbnd]S bond cleavage of aromatic isopropyl sulfides, which was catalyzed by hemin in assistance of Triton X-100. This aqueous catalytic system exhibited good functional group tolerance to a variety of sulfides and diazo esters. And the reaction mechanism was preliminarily proposed on the basis of designed reactions. Furthermore, the cleavage of C[sbnd]S bond followed by introducing a functional ester group to aromatic sulfides, may potentially be employed for the late stage functionalization (LSF) of organosulfur drug in the future.
MYOGLOBIN-BASED CATALYSTS FOR CARBENE TRANSFER REACTIONS
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Paragraph 0077; 00297; 00298, (2016/06/14)
Methods are provided for carrying out carbene transfer transformations such as olefin cyclopropanation reactions, carbene heteroatom-H insertion reactions (heteroatom = N, S, Si), sigmatropic rearrangement reactions, and aldehyde olefination reactions with high efficiency and selectivity by using a novel class of myoglobin-based biocatalysts. These methods are useful for the synthesis of a variety of organic compounds which contain one or more new carbon-carbon or carbon-heteroatom (N, S, or Si) bond. The methods can be applied for conducting these transformations in vitro (i.e., using the biocatalyst in isolated form) and in vivo (i.e., using the biocatalyst in a whole cell system).
Intermolecular carbene S-H insertion catalysed by engineered myoglobin-based catalysts
Tyagi, Vikas,Bonn, Rachel B.,Fasan, Rudi
, p. 2488 - 2494 (2015/03/30)
The first example of a biocatalytic strategy for the synthesis of thioethers via an intermolecular carbene S-H insertion reaction is reported. Engineered variants of sperm whale myoglobin were found to efficiently catalyze this C-S bond forming transformation across a diverse set of aryl and alkyl mercaptan substrates and α-diazoester carbene donors, providing high conversions (60-99%) and high numbers of catalytic turnovers (1100-5400). Furthermore, the enantioselectivity of these biocatalysts could be tuned through mutation of amino acid residues within the distal pocket of the hemoprotein, leading to myoglobin variants capable of supporting asymmetric S-H insertions with up to 49% ee. Rearrangement experiments support a mechanism involving the formation of a sulfonium ylide generated upon attack of the thiol substrate to a heme-bound carbene intermediate. This journal is
Synthesis and characterization of photoswitchable lipids containing hemithioindigo chromophores
Eggers,Fyles,Montoya-Pelaez
, p. 2966 - 2977 (2007/10/03)
The synthesis of four lipids containing the hemithioindigo chromophore as part of the fatty acid is described. Heck reaction of bromophenyl thioacetate esters with acrylonitrile, followed by reduction, ester hydrolysis, and Friedel-Craft acylation-cyclization gave a substituted thioindoxyl that condensed with an alkoxy benzaldehyde to produce the hemithioindigo. "Solventless" nitrile hydrolysis followed by mixed anhydride coupling of the acid with glycerophosphocholine produced lipids bearing two hemithioindigo chromophores. The photochemistry of various hemithioindigo derivatives was studied to confirm the expected photoisomerization in both homogeneous organic solution, and in vesicle bilayer membranes. Characteristic changes in the UV-visible spectra are consistent with fully reversible Z-E photoisomerization. Chromatographic separation of the Z and E isomers of a compound containing a single hemithioindigo chromophore confirmed the spectroscopic analysis and provided a quantitative analysis of the compositions of Z-E isomer mixtures.
SYNTHESIS AND SPECTRAL STUDIES OF SOME NOVEL ETHYL (SUBSTITUTED PHENYLTHIO) ACETATE AND PROPIONATE DERIVATIVES
Hamed, Ezzat E.,El-Bardan, A. A.,Moussa, Adel M.
, p. 269 - 274 (2007/10/02)
Ethyl (substituted phenylthio) acetate and propionate derivatives have been synthesised, their structures were proved by IR, NMR and mass spectra.Key words: Arylthioacetates; arylthiopropionates; NMR- and mass spectra
