7205-74-5Relevant academic research and scientific papers
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
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.
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
Tert-Butyl Sulfoxides: Key Precursors for Palladium-Catalyzed Arylation of Sulfenate Salts
Gelat, Fabien,Lohier, Jean-Fran?ois,Gaumont, Annie-Claude,Perrio, Stéphane
, p. 2011 - 2016 (2015/06/23)
The present report describes an efficient and clean generation of sulfenate salts (R1SO-) by pyrolysis of readily available tert-butyl sulfoxides to give sulfenic acids (R1SOH) and traceless isobutene, followed by hydrogen abstraction with a weak inorganic base (K3PO4). The relevance of this process was exemplified through an in situ palladium-catalyzed cross-coupling reaction with aryl halides/triflates leading to aryl sulfoxides. The operationally simple C-S bond-forming protocol developed uses Pd(dba)2 as catalyst and Xantphos as ligand in toluene or a toluene/H2O mixture. Further extensions include the use of di-tert-butyl sulfoxide as an equivalent for sulfur monoxide dianion (SO2-) and the development of diastereoselective versions in the [2.2]paracyclophane and biaryl series.
Diastereoconvergent synthesis of trans -5-hydroxy-6-substituted-2- piperidinones by addition-cyclization-deprotection process
Si, Chang-Mei,Huang, Wei,Du, Zhen-Ting,Wei, Bang-Guo,Lin, Guo-Qiang
supporting information, p. 4328 - 4331 (2014/09/30)
A diastereoselective one-pot approach to access trans-5-hydroxy-6- substituted-2-piperidinones by an addition-cyclization-deprotection process has been developed, in which the stereogenic center at the C-6 position was solely controlled by α-OTBS group. The utility of this transformation is demonstrated by the asymmetric synthesis of the enantiomer of (-)-CP-99,994.
Structural effects on the C-S bond cleavage in aryl tert -butyl sulfoxide radical cations
Cavattoni, Tullio,Del Giacco, Tiziana,Lanzalunga, Osvaldo,Mazzonna, Marco,Mencarelli, Paolo
, p. 4886 - 4894 (2013/07/11)
The oxidation of a series of aryl tert-butyl sulfoxides (4-X-C 6H4SOC(CH3)3: 1, X = OCH 3; 2, X = CH3; 3, X = H; 4, X = Br) photosensitized by 3-cyano-N-methylquinolinium perchlorate (3-CN-NMQ+) has been investigated by steady-state irradiation and nanosecond laser flash photolysis (LFP) under nitrogen in MeCN. Products deriving from the C-S bond cleavage in the radical cations 1+?-4+? have been observed in the steady-state photolysis experiments. By laser irradiation, the formation of 3-CN-NMQ? (λmax = 390 nm) and 1 +?-4+? (λmax = 500-620 nm) was observed. A first-order decay of the sulfoxide radical cations, attributable to C-S bond cleavage, was observed with fragmentation rate constants (k f) that decrease by increasing the electron donating power of the arylsulfinyl substituent from 1.8 × 106 s-1 (4 +?) to 2.3 × 105 s-1 (1 +?). DFT calculations showed that a significant fraction of the charge is delocalized in the tert-butyl group of the radical cations, thus explaining the small substituent effect on the C-S bond cleavage rate constants. Via application of the Marcus equation to the kinetic data, a very large value for the reorganization energy (λ = 62 kcal mol-1) has been calculated for the C-S bond scission reaction in 1+?-4 +?.
Mechanism of the oxidation of aromatic sulfides catalysed by a water soluble iron porphyrin
Baciocchi, Enrico,Gerini, Maria Francesca,Lanzalunga, Osvaldo,Lapi, Andrea,Lo Piparo, Maria Grazia
, p. 422 - 426 (2007/10/03)
The oxygen atom transfer-electron transfer (ET) mechanistic dichotomy has been investigated in the oxidation of a number of aryl sulfides by H2O2 in acidic (pH 3) aqueous medium catalysed by the water soluble iron(III) porphyrin 5,10,15,20-tetraphenyl-21H,23H-porphine-p,p′,p″,p?-tetrasulfo nic acid iron(III) chloride (FeTPPSCl). Under these reaction conditions, the iron-oxo complex porphyrin radical cation, P+ Fe(IV)=O, should be the active oxidant. When the oxidation of a series of para-X substituted phenyl alkyl sulfides (X = OCH3, CH3, H, Br, CN) was studied the corresponding sulfoxides were the only observed product and the reaction yields as well as the reactivity were little influenced by the nature of X as well as by the bulkiness of the alkyl group. Labelling experiments using H2 18O or H218O2 clearly indicated that the oxygen atom in the sulfoxides comes exclusively from the oxidant. Moreover, no fragmentation products were observed in the oxidation of a benzyl phenyl sulfide whose radical cation is expected to undergo cleavage of the β C-H and C-S bonds. These results would seem to suggest a direct oxygen atom transfer from the iron-oxo complex to the sulfide. However, competitive experiments between thioanisole (E° = 1.49 V vs. NHE in H2O) and N,N-dimethylaniline (E° = 0.97 V vs. NHE in H2O) resulted in exclusive N-demethylation, whereas the oxidation of N-methylphenothiazine (10, E° = 0.95 V vs. NHE in CH3CN) and N,N-dimethyl-4-methylthioaniline (11, E° = 0.65 V vs. NHE in H2O) produced the corresponding sulfoxide with complete oxygen incorporation from the oxidant. Since an ET mechanism must certainly hold in the reactions of 10 and 11, the oxygen incorporation experiments indicate that the intermediate radical cation, once formed, has to react with PFe(IV)=O (the reduced form of the iron-oxo complex which is formed by the ET step) in a fast oxygen rebound. Thus, an ET step followed by a fast oxygen rebound is also suggested for the other sulfides investigated in this work.
