1541-10-2Relevant articles and documents
A capped trigonal pyramidal molybdenum hydrido complex and an unusually mild sulfur-carbon bond cleavage reaction
Morris, Robert H.
, p. 11032 - 11035 (2017)
DFT calculations reveal that a reported molybdenum hydride complex has an unprecedented geometry with the molybdenum in the base of trigonal pyramid defined by three thiolate ligands with a phosphine ligand on the apex and a hydride capping a PS2 face. This complex reacts with methanol to produce a sulfido complex by a new reaction: the protonation of an ipso carbon of a thiolate ligand by coordinated methanol.
A general thiolation of magnesium organometallics using tetramethylthiuram disulfide
Krasovskiy, Arkady,Gavryushin, Andrey,Knochel, Paul
, p. 2691 - 2693 (2005)
The reaction of various functionalized aryl and heteroaryl bromides with i-PrMgCl·LiCl produces highly reactive Grignard reagents complexed by LiCl, which react with tetramethylthiuram disulfide [(Me2NCS 2)2] leading to th
Electrophilic alkylation of pseudotetrahedral nickel(II) arylthiolate complexes
Deb, Tapash,Jensen, Michael P.
supporting information, p. 87 - 96 (2015/03/03)
A kinetic study is reported for reactions of pseudotetrahedral nickel(II) arylthiolate complexes [(TpR,Me)Ni-SAr] (TpR,Me = hydrotris{3-R-5-methyl-1-pyrazolyl}borate, R = Me, Ph, and Ar = C6H5, C6H4-4-Cl, C6H4-4-Me, C6H4-4-OMe, 2,4,6-Me3C6H2, 2,4,6-iPr3C6H2) with organic electrophiles R'X (i.e., MeI, EtI, BzBr) in low-polarity organic solvents (toluene, THF, chloroform, dichloromethane, or 1,2-dichloroethane), yielding a pseudotetrahedral halide complex [(TpR,Me)Ni-X] (X = Cl, Br, I) and the corresponding organosulfide R'SAr. Competitive reactions with halogenated solvents and adventitious air were also examined. Akin to reactions of analogous and biomimetic zinc complexes, a pertinent mechanistic question is the nature of the reactive nucleophile, either an intact thiolate complex or a free arylthiolate resulting from a dissociative pre-equilibrium. The observed kinetics conformed to a second-order rate law, first order with respect to the complex and electrophile, and no intermediate complexes were observed. In the absence of a mechanistically diagnostic rate law, a variety of mechanistic probes were examined, including kinetic effects of varying the metal, solvent, electrophile, and temperature, as well as the 3-pyrazolyl and arylthiolate substituents. Compared to zinc analogues, the effect of Ni-SAr covalency is also of interest herein. The results are broadly interpreted with respect to the disparate mechanistic pathways.
Synthesis, structure and reactivity of Ni site models of [NiFeSe] hydrogenases
Wombwell, Claire,Reisner, Erwin
, p. 4483 - 4493 (2014/03/21)
A series of structural models of the Ni centre in [NiFeSe] hydrogenases has been developed which exhibits key structural features of the Ni site in the H2 cycling enzyme. Specifically, two complexes with a hydrogenase-analogous four-coordinate 'NiS3Se' primary coordination sphere and complexes with a 'NiS2Se2' and a 'NiS 4' core are reported. The reactivity of the complexes towards oxygen and protons shows some relevance to the chemistry of [NiFeSe] hydrogenases. Exposure of a 'NiS3Se' complex to atmospheric oxygen results in the oxidation of the selenolate group in the complex to a diselenide, which is released from the nickel site. Oxidation of the selenolate ligand on Ni occurs approximately four times faster than oxidation with the analogous sulfur complex. Reaction of the complexes with one equivalent of HBF4 results in protonation of the monodentate chalcogenolate and the release of this ligand from the metal centre as a thiol or selenol. Unrelated to their biomimetic nature, the complexes serve also as molecular precursors to modify electrodes with Ni-S-Se containing particles by electrochemical deposition. The activated electrodes evolve H2 in pH neutral water with an electrocatalytic onset potential of -0.6 V and a current density of 15 μA cm-2 at -0.75 V vs. NHE.
Facile introduction of SH group on aromatic substrates via electrophilic substitution reactions
Becht, Jean-Michel,Wagner, Alain,Mioskowski, Charles
, p. 5758 - 5761 (2007/10/03)
Herein, we describe a mild and efficient two-step procedure to introduce a thiol group on aromatic substrates. First, reaction with an activated sulfoxide leads to an arylsulfonium salt intermediate. Then, two successive β-elimination-based dealkylation reactions afford the desired arylthiols in good to excellent yields.
Rhodium-Catalyzed Rearrangement of α-Diazo Thiol Esters to Thio-Substituted Ketenes. Application in the Synthesis of Cyclobutanones, Cyclobutenones, and β-Lactams
Lawlor, Michael D.,Lee, Thomas W.,Danheiser, Rick L.
, p. 4375 - 4384 (2007/10/03)
Exposure of α-diazo thiol esters (1) to the action of catalytic rhodium(II) acetate leads to a remarkably facile "thia-Wolff rearrangement", producing thio-substituted ketenes which combine with a variety of ketenophiles to provide access to α-thiocyclobutanones, cyclobutenones, and β-lactams. Reductive desulfurization of these cycloadducts takes place under mild conditions and in excellent yield, and this sequence thus represents a useful new alternative to the existing dichloroketene-based methodology for the synthesis of four-membered carbocycles and heterocycles.
Formation by SRN1 reactions and 1H N.M.R. properties of sterically encumbered 2,4,6-triaIkyIphenyl p-nitrobenzyl sulfides
Look, Kai,Norris, Robert K.
, p. 1077 - 1083 (2007/10/03)
Sterically hindered p-nitrobenzylic chlorides (1) and (2) react with the sodium salts of 2,4,6-trialkylbenzenethiols (3a)-(5a) by the SRN1 reaction to give good yields of the corresponding p-nitrobenzylic aryl sulfides (6)-(10). For example, th
Catalytic kinetic resolution of 5-alkoxy-2(5H)-furanones
Faber, Wijnand S.,Kok, Johan,De Lange, Ben,Feringa, Ben L.
, p. 4775 - 4794 (2007/10/02)
The kinetic resolution of racemic 5-alkoxy-2(5H)-furanones, using a chiral aminoalcohol catalyzed 1,4-addition of arylthiols, was examined. Using various butenolides it was shown that a γ-alkoxy substituent appears to be essential to reach high enantioselectivities whereas electron-donating substituents in the arylthiols also increase the selectivity. Cinchona alkaloids are the preferred catalysts for the kinetic resolution, with quinine and quinidine leading to the most efficient and selective thiol additions. A remarkable dilution effect and a strong dependency on the mode of addition of reactants were observed. Optimization studies are presented of the kinetic resolution of 5-methoxy-2(5H)-furanone 2 resulting in (R)-2 or (S)-2 with enantiomeric excesses exceeding 90%. A mechanism for the quinine (quinidine) catalyzed kinetic resolution is given.
Process for phenol alkylthiolation and its application to the synthesis of 4-acyl-2-alkylthiophenols
-
, (2008/06/13)
The invention relates to the preparation of alkylthiophenols by reaction of a dialkyl disulphide with a phenol. In the process according to the invention, the reaction is carried out in the presence of aluminum chloride or of ferric chloride in a solvent of the alkylbenzene type or, soley in the case of methylthiolation, in an excess of dimethyl disulphide. This process makes it possible, in particular to obtain, with a selectivity and in a yield which are excellent, 2-alkylthiophenols which may then be converted into 4-acyl-2-alkylthiophenols by means of a reaction at a temperature ranging from 40° to 100° C. with a complex BF3 :2RCOOH where R denotes an alkyl or propenyl radical, in a proportion of 10 to 15 moles of complex per mole of 2-alkylthiophenol.
RADIKALIONEN 89. EINELEKTRONEN-OXIDATIONEN VON DIARYLDISULFIDEN MIT AlCl3/H2CCl2
Bock, Hans,Rittmeyer, Peter
, p. 261 - 292 (2007/10/02)
The single electron oxidation of 14 alkyl and alkoxy substituted diaryldisulfides by AlCl3/H2CCl2 has been investigated by ESR/ENDOR spectroscopy.The radical cations observed prove the following skeletal rearrangements: Those with ring hydrogens in ortho positions to the disulfide bridge preferentially form thianthrene derivatives.The isomeric dinaphthyl disulfides react differently, the 2,2'-isomer yielding the dibenzothianthrene radical cation and the 1,1'-isomer the well-known naphthalene-1,8-disulfide radical cation.For all diaryl disulfides with completely alkyl- or methoxy-blocked ortho positions, oxidative desulfuration is observed.As substantiated by additional (2)D and (33)S isotope marking, the bis(2,5-dimethoxyphenyl)disulfide reacts both to the corresponding thianthrene derivative as well as via desulfuration to the radical cation of the monosulfide.Accompanying cyclovoltammetric and photoelectron spectroscopic measurements prove that all ESR spectroscopically detected radical cations result from compounds Ar-S-Ar, Ar-SS-Ar and Ar(S)2Ar with rather low oxidation or ionisation potentials and thus suggest that each the most easily oxidized paramagnetic species is observed in the rather complex product mixtures, which form on AlCl3/H2CCl2 oxidation of diaryldisulfides. Key words: Diaryl disulfides; one-electron oxidation; radical cations; ESR/ENDOR spectra.
