19207-87-5Relevant academic research and scientific papers
On the development of a nucleophilic methylthiolation methodology
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
, p. 5420 - 5426 (2020)
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
Electron transfer reactions (ETR) of tert-butyl perbenzoates with dimethyl sulfide: The rates controlled by translational entropy
Kim, Sung Soo,Lim, Sang Hak
, p. 625 - 629 (2008/02/08)
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
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.
Pryor,Hendrickson Jr.
, p. 7114 - 7122 (2007/10/02)
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.
