- Electrochemical Oxidation Enables Regioselective and Scalable α-C(sp3)-H Acyloxylation of Sulfides
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A highly selective, environmentally friendly, and scalable electrochemical protocol for the construction of α-acyloxy sulfides, through the synergistic effect of self-assembly-induced C(sp3)-H/O-H cross-coupling, is reported. It features exceptionally broad substrate scope, high regioselectivity, gram-scale synthesis, construction of complex molecules, and applicability to a variety of nucleophiles. Moreover, the soft X-ray absorption technique and a series of control experiments have been utilized to demonstrate the pivotal role of the self-assembly of the substrates, which indeed is responsible for the excellent compatibility and precise control of high regioselectivity in our electrochemical protocol.
- Wang, Huamin,He, Meng,Li, Yongli,Zhang, Heng,Yang, Dali,Nagasaka, Masanari,Lv, Zongchao,Guan, Zhipeng,Cao, Yangmin,Gong, Fengping,Zhou, Zhilin,Zhu, Jingyun,Samanta, Supravat,Chowdhury, Abhishek Dutta,Lei, Aiwen
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supporting information
p. 3628 - 3637
(2021/04/07)
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- On the development of a nucleophilic methylthiolation methodology
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Methylthiolation reactions are usually explored to access organosulfur compounds using methanethiol, an extremely flammable and toxic compound. Herein, methylthiomethyl esters were successfully applied as novel methylthiolation reagents in a low cost, transition-metal-free methodology. These reagents allowed the methylthiolation of a wide scope of chalcones, acyl ester derivatives and Morita-Baylis-Hillman acetates with good group tolerance, affording the methylthiolated products in moderate to excellent yields. The reaction mechanism was investigated through several control experiments, as well as by theoretical calculations employing Density Functional Theory. The results strongly support that a sulfurane and a sulfonium ylide appear as key intermediates and that a Pummerer type rearrangement is also crucial for the formation of this novel reagent. Furthermore, the methylthiolation mechanism is likely to proceed through the nucleophilic attack of the reagent, followed by an entropically favoured step involving the acetate attack to the positively charged species, then releasing the product. This journal is
- Carvalho, Bernardo Basbaum Portinho De Puga,Amaral, Adriane Antonia Pereira,De Castro, Pedro P?ssa,Ferreira, Fernanda Cerqueira Moreira,Horta, Bruno Araújo Cautiero,Amarante, Giovanni Wilson
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p. 5420 - 5426
(2020/08/03)
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- Fe2O3-catalyzed Pummerer rearrangement of acyl chlorides and sulfoxides: Facile synthesis of alkylthiomethyl ester
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A simple, effective approach for the Pummerer rearrangement of acyl chlorides with sulfoxides by using a low-cost and more abundant Fe catalyst has been described. The alkylthiomethyl ester products were prepared in good to excellent yields for a range of different substrates including asymmetrical sulfoxides and acyl chlorides with a variety of functional groups under mild reaction conditions. The reaction features short reaction time, simple manipulation, cheap reagents and a broad substrate scope. Single crystal X-ray analysis of a representative methylthiomethyl (MTM) group containing product was also reported.
- Xing, Haotian,Chen, Long,Jia, Yimin,Jiang, Zhongxing,Yang, Zhigang
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supporting information
p. 2199 - 2202
(2017/05/16)
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- Method for preparing alkylthiomethyl ester compounds
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The invention discloses a method for preparing alkylthiomethyl ester compounds and belongs to the field of organic chemistry. The method disclosed by the invention comprises the following steps: dissolving sulfoxide, an iron salt reagent and an alkali in a non-protonic solvent under inert gas shielding; adding an acyl chloride reagent into the system, stirring and reacting to enable alpha-carbon rearranged by sulfoxide molecules to combine with acyloxy transformed by acyl chloride molecules, thereby obtaining the alkylthiomethyl ester. The method disclosed by the invention is simple in reaction, mild in conditions, low in cost and wide in application range; and the reaction product can become an important and effective carboxyl protecting group, and the absorption effect of certain drugs can be improved.
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Paragraph 0022; 0023
(2017/08/31)
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- A direct conversion of carboxylic acids to methylthiomethyl esters using a microwave-assisted pummerer rearrangement with dimethylsulfoxide
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A simple microwave-assisted method for the conversion of carboxylic acids to MTM esters is presented. This new process allows for rapid introduction of an MTM ester protecting group to a variety of carboxylic acids including alkyl, electron-rich aromatic,
- McCarthy, Allison,Spatney, Russell,Manpadi, Madhuri,Myers, Brian J.,Zimmerman, Jake R.
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supporting information; experimental part
p. 4782 - 4784
(2012/09/07)
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- Electron transfer reactions (ETR) of tert-butyl perbenzoates with dimethyl sulfide: The rates controlled by translational entropy
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Various tert-butyl perbenzoates were prepared according to the known methods. The mixtures of tert-butyl perbenzoate and dimethyl sulfide underwent thermolysis at several temperatures (T°C: 80, 90, 100, and 110). The rates of consumption of the peresters (kobs) were obtained from In C 0/Ct = kobs × t where Co and Ct are the concentration of the perester at time 0 and t, respectively. For example: The decrease of the perester satisfied pseudo first order kinetics, and kobs were determined. kHom. and k ET were obtained from kobs = kHom. + k ET[CH3SCH3] where [CH3SCH 3]/[perester] > 10. kET and its relative rates are produced from plot of kobs against [CH3SCH3]. Hammett correlation are plotted against σ and σ+ in which σ is better correlated than σ+. Hammett ρ could be considered selectivity which stays constant irrespective of temperature. The phenomenon is not consistent with reactivity/selectivity principle. The differential activation entropies linearly increase with substituent constant σ to give slope of 2.63 while the similar slope for differential enthalpies shows much lower value of 0.892. The dominance of differential entropic terms clearly indicates the entropy control of the rates. Copyright
- Kim, Sung Soo,Lim, Sang Hak
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p. 625 - 629
(2008/02/08)
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- Synthesis of Manwuweizic acid, an anticancer triterpenoid
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Manwuweizic acid (1), an anticancer triterpenoid isolated from Scisandra propinqua, was synthesized from lanosterol (2) by stereoselective introduction of the (Z) α,β-unsaturated carboxylic terminal of the side chain and by abnormal Beckmann rearrangement
- Liu,Tao
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p. 6793 - 6798
(2007/10/02)
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- REACTION OF NUCLEOPHILES WITH ELECTRON ACCEPTORS BY SN2 OR ELECTRON TRANSFER (ET) MECHANISMS: TERT-BUTYL PEROXYBENZOATE/DIMETHYL SULFIDE AND BENZOYL PEROXIDE/N,N-DIMETHYLANILINE SYSTEMS.
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This study is one of a series that probes the reactions of nucleophiles with peroxides, reactions that can occur either by an initial S//N2 reaction or by an electron-transfer (ET) reaction. The products and kinetics are reported for the reaction of dimethyl sulfide and a series of ring-substituted aryl methyl sulfides with tert-butyl peroxybenzoate (TBP) and four ring-substituted TPB's. Kinetic analysis allows the separation of the rate constants for unimolecular homolysis (k//1) and those for the decomposition of the TBP by the sulfide (k//2). The bimolecular reaction is accelerated by electron-withdrawing substituents in the TBP; for example, when 3,5-(NO//2)//2-TBP is used, k//2/k//1 is 12,000. The products that are formed are consistent with a radical process; however, this evidence is not regarded as conclusive.
- Pryor,Hendrickson Jr.
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p. 7114 - 7122
(2007/10/02)
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- METHYLTHIOMETHYL ESTERS FROM ACID CHLORIDES REEXAMINATION OF A REPORTED β-KETOSULFOXIDE SYNTHESIS
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Reexamination of the reported (1) synthesis of β-ketosulfoxides from acid chlorides and reagent 2 revealed that the products formed were actually methylthiomethyl esters (4).
- Kukla, Michael J.
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p. 4539 - 4540
(2007/10/02)
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- t-Butyl Bromide-Dimethyl Sulphoxide Reactions. Pummerer-like Reaction with Carboxylic Acids and N-Protected Amino-acids
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t-Butyl bromide-activated dimethyl sulphoxide reacted with carboxylic acids and differently N-protected amino-acids in the presence of a base (NaHCO3 or Et3N).High to quantitative yields of methylthiomethyl (MTM) esters were obtained in all cases without interference by other functional groups or racemization.The mechanism of the reaction is discussed on the basis of the products formed, of spectral data, and of other miscellaneous experiments.
- Dossena, Arnaldo,Marchelli, Rosangela,Casnati, Guiseppe
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p. 2737 - 2739
(2007/10/02)
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- Methylthiomethyl Nitrones Derived from the Oximes of Benzil: Preparation, Thermolysis, and Photolysis
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Reaction between benzil E-monoxime, N-chlorosuccinimide, dimethyl sulphide, and triethylamine gave a mixture of the isomeric C-benzoyl-C-phenyl-N-methylthiomethyl nitrones (2) and (3).The isomers were thermally and photochemically interconverted, and longer heating afforded benzoin, 2-methylthio-4,5-diphenyl-1,3-oxazole, 4,5-diphenyl-1,3-oxazole, and benzil O-methylthiomethyl-Z-oxime as products.Photolysis gave the first three products as well as dimethyl disulphide.Mechanisms are suggested for these reactions.Attempted alkylation of benzil E- and Z-monoximes with methylthiomethyl chloride gave methylthiomethyl benzoate, phenyl cyanide, and benzoic acid, for which a fragmentation mechanism is proposed.Benzoin E-oxime underwent Beckmann fragmentation when formation of nitrone was attempted.
- Ooi, Ngan Sim,Wilson, David A.
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p. 4501 - 4512
(2007/10/02)
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