21681-88-9Relevant academic research and scientific papers
Unusual Application for Phosphonium Salts and Phosphoranes: Synthesis of Chalcogenides
Moura, Igor M. R.,Tranquilino, Arisson,Sátiro, Barbara G.,Silva, Ricardo O.,De Oliveira-Silva, Diogo,Oliveira, Roberta A.,Menezes, Paulo H.
, p. 5954 - 5964 (2021/05/04)
A novel strategy for the synthesis of sulfides and selenides from phosphonium salts and thio- or selenesulfonates, commercially available compounds, is described. When phosphoranes were used in the reaction, different products were obtained. The methodology does not require the use of metals, reactive species, or anhydrous conditions to be performed.
Dealkylative intercepted rearrangement reactions of sulfur ylides
Empel, Claire,Hock, Katharina J.,Koenigs, Rene M.
supporting information, p. 338 - 341 (2019/01/09)
Sulfur ylides are well-known to undergo sigmatropic rearrangement reaction. Herein, we describe a novel reactivity of sulfur ylides, which provides access to the product of a formal functional group metathesis upon dealkylative interception of the rearrangement process. Using a simple iron catalyst and in situ generated diazoalkanes this method provides access to α-mercaptoacetonitrile derivatives.
Decarboxylative Cyanation of Aliphatic Carboxylic Acids via Visible-Light Flavin Photocatalysis
Ramirez, Nieves P.,K?nig, Burkhard,Gonzalez-Gomez, Jose C.
supporting information, (2019/03/08)
An operationally simple method is disclosed for the decarboxylative cyanation of aliphatic carboxylic acids at room temperature. Riboflavin tetraacetate, which is an inexpensive organic photocatalyst, promotes the oxidation of carboxylic acids upon visible-light activation. After decarboxylation, the generated radicals are trapped by TsCN, yielding the desired nitriles without any further additive, in a redox-neutral process. Importantly, this protocol can be adapted to flow conditions.
Iron-catalysed carbene-transfer reactions of diazo acetonitrile
Empel, Claire,Hock, Katharina J.,Koenigs, Rene M.
supporting information, p. 7129 - 7133 (2018/10/24)
A continuous-flow protocol for the synthesis of diazo acetonitrile was developed. It was further applied in iron-catalysed insertion reactions of diazo acetonitrile into N-H and S-H bonds to yield valuable α-substituted acetonitrile, including gram-scale synthesis.
Cs2CO3-promoted carbon–sulfur bond construction via cross dehydrogenative coupling of thiophenols with acetonitrile
Chen, Qian,Huang, Yulin,Wang, Xiaofeng,Wen, Chunxiao,Yan, Xinxing,Zeng, Jiekun
supporting information, p. 3928 - 3931 (2017/09/21)
A novel protocol for the construction of carbon–sulfur bonds has been achieved via halogen-free Cs2CO3-promoted cross dehydrogenative coupling (CDC) of thiophenols with acetonitrile. This transformation provides a straightforward route to the synthesis of sulfenylated acetonitriles in up to 80% yield.
Nitrilase-catalysed hydrolysis of cyanomethyl p-tolyl sulfoxide: stereochemistry and mechanism
Kielbasinski, Piotr,Rachwalski, Michal,Mikolajczyk, Marian,Rutjes, Floris P.J.T.
, p. 562 - 567 (2008/09/20)
Several commercially available nitrilases have been used for the enantioselective hydrolysis of cyanomethyl p-tolyl sulfoxide into the corresponding amide and acid, which are formed in different proportions and with varying stereoselectivities, depending on the nitrilase involved. It was shown that the externally added amide is not transformed into the acid, which can be explained by assuming that both products must be produced in concurrent reactions. It was also demonstrated that the absolute configuration of the substrate exerts substantial influence on the product ratio. Two alternative explanations of the stereochemical course are presented.
Diastereoselective conversion of sulfides into sulfoxides. 1,5- and 1,6-asymmetric induction
Bower, Justin F.,Martin, Christopher J.,Rawson, David J.,Slawin, Alexandra M. Z.,Williams, Jonathan M. J.
, p. 333 - 342 (2007/10/03)
The diastereoselective oxidation of sulfides into sulfoxides has been achieved with enantiomerically pure dihydrooxazole auxiliaries. When an additional hydroxymethyl substituent is present, diastereocontrol is very high and 1,5-asymmetric induction has been achieved with up to 96:4 selectivity, and 1,6-asymmetric induction has been achieved with up to 97:3 selectivity in the absence of any additional chiral agents.
meso-Tetraphenylporphinatoiron Catalysed Reductive Cleavage of some S-O, S-N, and S-C Bonds in Sulphoxides and Sulphilimines
Nagata, Toshiyuki,Fujimori, Ken,Yoshimura, Toshiaki,Furukawa, Naomochi,Oae, Shigeru
, p. 1431 - 1435 (2007/10/02)
meso-Tetraphenylporphinatoiron chloride (TPPFeIIICl) has been found to catalyse the reductive cleavage of semipolar S-O and S-N bonds in aromatic sulphoxides and sulphilimines respectively with both 1-benzyl-1,4-dihydronicotinamide (BNAH) and sodium borohydride.Sulphoxides bearing electron-withdrawing substituents are much more readily reduced than those with electron-donating groups.The rate of reduction by the TPPFeIII/BNAH system decreases in the following order: N-unsubstituted sulphilimines > N-tosylsulphilimines > aromatic sulphoxides.During the reaction with sulphoxides, the formation of the μ-oxo dimer of TPPFeIII has been observed.Under the same conditions, concurrent reductive cleavage of the S-C bond was observed with sulphoxides bearing an electron-withdrawing group at the α-position.Control experiments revealed that the reductive S-dealkylation of these sulphides is accompanied by the major S-deoxygenation reaction.Plausible mechanisms are discussed.
Intramolecular Stereospecific Pummerer Reactions of Aryl (Substituted-methyl) Sulfoxides Bearing Electron-withdrawing Groups with Acetic Anhydride
Numata, Tatsuo,Itoh, Osamu,Yoshimura, Toshiaki,Oae, Shigeru
, p. 257 - 265 (2007/10/02)
The Pummerer reaction of optically active cyanomethyl aryl sulfoxides with acetic anhydride gave the corresponding α-acetoxy sulfides which were induced with a partial asymmetry nearly 30percent at α-carbon, while the 18O-label of the original sulfoxides was retained in more than 85percent in the resulting ester, the Pummerer reaction product.Kinetic experiments with cyanomethyl (p-substituted phenyl) sulfoxides and α,α-dideuterated cyanomethyl p-tolyl sulfoxide in the reaction with acetic anhydride containing a small amount of acetic acid revealed that the rates were correlated with Hammett ?-values and ρ-value of -0.70 was obtained, while the kinetic isotope effect was practically nil, i.e., kH/kD=1.01.These observations indicate clearly that the rearrangement is intramolecular and proceeds via forming a very intimate ion-pair and the rate-determining step is believed to be the S-O bond cleavage after the initial reversible acylation and deprotonation.Elimination of acetic acid proceeds through the Eleb type process.The uneven distribution of 18O in the two oxygens of the resulted ester, i.e., ether and carbonyl oxygens, suggests the recombination of the α-sulfenyl carbonium ion and acetate ion to be very rapid.The pummerer reaction of optically active N,N-dimethyl-p-tolyl-sulfinylacetamide with excess acetic anhydride also gave the corresponding α-acetoxy sulfide in optically active form.In the presence of di-cyclohexylcarbodiimide (DCC), the Pummerer reaction was found to be highly stereoselective affording the corresponding α-acetoxy sulfide with 65percent e.e.Other optically active α-carbonyl-substituted alkyl sulfoxides, i.e., ethyl p-tolylsulfinylacetate and ω-(p-tolylsulfinyl)acetophenone also gave the corresponding highly optically active Pummerer rearrangement products in the treatment with acetic anhydride/DCC system.The Pummerer reaction of the 18O-labeled sulfoxides with acetic anhydride/DCC system gave the corresponding α-acetoxy sulfides which retained much of the original 18O-labels of the sulfoxides.These observations reveal clearly that in the Pummerer reaction of these compounds the acetoxyl migration is intramolecular and takes place through intimate ion-pairs.
