702-00-1Relevant articles and documents
Yb(iii)-catalysedsyn-thioallylation of ynamides
Dutta, Shubham,Gandon, Vincent,Gogoi, Manash Protim,Mallick, Rajendra K.,Prabagar, B.,Sahoo, Akhila K.,Vanjari, Rajeshwer,Yang, Shengwen
supporting information, p. 7521 - 7524 (2021/08/05)
Reported herein is asyn-thioallylation of ynamides incorporating a sulfide moiety at the α-position and an allyl group at the β-position of the ynamide. The transformation is successful under ytterbium(iii)-catalysis, providing access to highly substituted thioamino-skipped-dienes with broad substrate scope. Thus, tetrasubstituted olefins (with four different functional groups: amide, phenyl, thioaryl/alkyl, and allyl on the carbon centers) are made in a single step from readily accessible ynamides, preserving complete atom economy. The reaction can be extended to the synthesis of selenoamino dienes by ynamidesyn-selenoallylation. DFT studies and control experiments provide insight into the reaction mechanism.
Aqueous hemin catalyzed sulfonium ylide formation and subsequent [2,3]-sigmatropic rearrangements
Xu, Xiaofei,Li, Chang,Tao, Zhihao,Pan, Yuanjiang
supporting information, p. 1245 - 1249 (2017/08/15)
A mild hemin catalytic system for sulfonium ylide generation via a metal carbenoid and a subsequent [2,3]-sigmatropic rearrangement reaction in aqueous solvent is well-established, with the assistance of cyclodextrin (CD) and Triton X-100. The protocol displays high catalytic activity with a broad substrate scope of aryl/alkyl allyl sulfides and diazo reagents, affording homoallyl sulfide products in up to 99% yield. Notably, this catalytic system is successful for water-insoluble allyl sulfides but ineffective for allyl amines or allyl ethers. Moreover, an unprecedented cascade reaction of sulfonium ylide formation, [2,3]-sigmatropic rearrangement and C-H insertion was reported.
Expanding the horizon of intermolecular trapping of in situ generated α-oxo gold carbenes: Efficient oxidative union of allylic sulfides and terminal alkynes via C-C bond formation
Li, Jiabin,Ji, Kegong,Zheng, Renhua,Nelson, Jonathan,Zhang, Liming
supporting information, p. 4130 - 4133 (2014/04/03)
With a new P,S-bidentate phosphine as the ligand to gold(i), the α-oxo gold carbenes generated in situ via gold-catalyzed intermolecular oxidation of terminal alkynes were effectively trapped by various allylic sulfides, resulting in the formation of α-aryl(alkyl)thio-γ,δ- unsaturated ketones upon facile [2,3]sigmatropic rearrangements. This journal is the Partner Organisations 2014.
Highly chemoselective synthesis of aryl allylic sulfoxides through calcium hypobromite oxidation of aryl allylic sulfides
Pace, Vittorio,Castoldi, Laura,Holzer, Wolfgang
supporting information; experimental part, p. 967 - 972 (2012/03/11)
A highly chemoselective oxidation of widely substituted aryl allylic sulfides, prepared by allylation of arylthioethers with KF-Celite, to the corresponding aryl allylic sulfoxide was achieved by employing calcium hypobromite. Neither over-oxidation to sulfones nor halogenation of the aromatic rings was observed. The protocol may be successfully applied for the oxidation of substituted allylic systems (i.e., 2-haloallyl) that per se could interact with the oxidizing agent.
Catalytic activation of diazo compounds using electron-rich, defined iron complexes for carbene-transfer reactions
Holzwarth, Michael S.,Alt, Isabel,Plietker, Bernd
supporting information; experimental part, p. 5351 - 5354 (2012/07/14)
Carbene transfer: The electron-rich iron complex Bu4N[Fe(CO) 3(NO)] efficiently catalyzes different carbene-transfer reactions. Various diazo compounds can be used. The high stability of the employed iron complexes is demonstrated by the generation of the diazo reagent in situ and a sequential iron-catalyzed allylic sulfenylation/Doyle-Kirmse reaction. Copyright
Reactions of 2-(α-Haloalkyl)thiiranes with nucleophilic reagents: V.* Reactions of 2-(α-chloroalkyl)thiiranes with organolithium compounds
Tomashevskii,Sokolov,Potekhin
experimental part, p. 1822 - 1825 (2011/04/17)
2-(α-Haloalkyl)thiiranes reacted with methyl-, butyl-, and phenyllithium to give the corresponding allyl sulfides. The reactions of diastereoisomeric erythro-and threo-2-(1-chloroethyl)thiiranes with phenyllithium were stereospecific, and they afforded (E)-and (Z)-1-phenylsulfanylbut-2-enes, respectively. 3-Chloromethyl-2,2- dimethylthiirane and phenyllithium gave rise to a mixture of 3-methyl-3-phenylsulfanylbut-1-ene and 3-methyl-1-phenylsulfanylbut-2-ene. The reactions of 2-chloromethylthiiranes with phenyllithium and methyllithium in the presence of a catalytic amount of copper(I) iodide (10 mol %) led to the formation of substituted thiiranes as the major products. Mechanisms of the observed transformations are discussed. Pleiades Publishing, Ltd., 2010.
On the reactivity of indium(III) benzenechalcogenolates (chalcogen = sulfur and selenium) towards organyl halides for the synthesis of organyl phenyl chalcogenides
Peppe, Clovis,Borges De Castro, Lierson
experimental part, p. 678 - 683 (2009/10/30)
The reactivity of indium(III) benzenechalcogenolates (chalcogen = sulfur, selenium) towards organyl halides (organyl = alkyl, allyl, benzyl, acyl) was examined. A practical one-pot method to prepare organyl phenyl chalcogenides indium metal and diphenyl dichalcogenide was found. The coupling is fairly broad in scope and generally works better organyl halides capable to produce stable carbocations.
Synthesis of allylsilanes by reductive lithiation of thioethers
Streiff, Stephane,Ribeiro, Nigel,Desaubry, Laurent
, p. 7592 - 7598 (2007/10/03)
Although much work in reductive lithiation has been done, the utilization of allylthioethers bearing various substituents to prepare allylsilanes has not been explored. The main reason clearly stems from the anticipated lack of regioselectivity. We describe herein the first study on the regioselectivity of the reductive silylation involving dissymmetric allylthioethers. We surveyed a broad spectrum of parameters and showed that this process displays a great dependence of the reaction conditions. We also discovered that an electron transporter, DBB or naphthalene, can cleave THF at room temperature by sonication, to generate a strong base, 4-lithiobutoxide. This feature was successfully exploited to the straightforward synthesis of bis-silanes in one pot. Examples are provided for maximizing both the chemical yield and the regioselectivity of the reductive silylation through the tuning of the reaction conditions. By changing these conditions, several allylsilanes can be selectively synthesized from one thioether.
Aromatic Allylsulfenylation with in Situ Generated Allylic Thiols under the Heck Conditions
Harayama, Hiroto,Nagahama, Takayuki,Kozera, Toyohiro,Kimura, Masanari,Fugami, Keigo,Tanaka, Shuji,Tamaru, Yoshinao
, p. 445 - 456 (2007/10/03)
A wide structural variety of S-allylic thiocarbamates 2 can be prepared in good yields by the rearrangement of O-allylic thiocarbamates 1 under three different conditions: thermal activation (neat, 120-150°C), palladium(0) (25-65 °C), and palladium(II) catalysis (25-65°C). Of the two possible regioisomers of unsymmetrical S-allylic thiocarbamates 2, those of higher thermodynamic stability can be prepared in high purity under either thermal activation or palladium(0) catalysis. Although the thermodynamically less stable regioisomers of 2 are, in general, hard to be prepared in high purity, some of them (e.g., 2d and 2h′) can be obtained with an exclusive or high selectivity by the catalysis of palladium(II). The stereoisomeric pair of 2j and 2j′ can be prepared selectively by the palladium(0)-catalyzed rearrangement of 1j and 1k, respectively. These reactions proceed with retention of configuration at the allylic stereocenters, S-Allylic (2) and S-alkyl thiocarbamates (7) undergo fragmentation to generate thiolates in the presence of inorganic bases (e.g., K2CO3, K2CO3·-Et4N+I-) by heating in an aprotic solvent; the thus-formed thiolates react with aromatic iodides and vinyl bromides in the presence of palladium(0) complexes to furnish aryl and vinyl sulfides, respectively. A wide variety of aryl sulfides can be prepared in good yields irrespective of the kind of substituents and their substitution positions (o-, m-, p-) under conditions B [Pd(OAc)2, PPh3, K2CO3·Et4N+I-, dioxane, 100°C]. Under conditions E [Pd(OAc)2, PPh3, Cs2CO3, dioxane, 100°C], better yields result specifically for the sulfenylation of aromatic iodides bearing substituents having large Hammett σ constants.
Clocking Tertiary Cyclopropylcarbinyl Radical Rearrangements
Engel, Paul S.,He, Shu-Lin,Banks,Ingold,Lusztyk
, p. 1210 - 1214 (2007/10/03)
Three independent methods have been employed to estimate the rate constant, k1, for ring-opening of the 2-cyclopropyl-2-propyl radical, 1, at room temperature. These three estimates are based on chemical trapping of 1 and the ring-opened 4-methylpent-3-ene-1-yl radical by thiophenol (k1 = (1.65 ± 0.41) × 107 M-1 s-1), 9-azabicyclo[3.3.1]nonane-N-oxyl (k1 = (1.76 ± 0.34) × 107 M-1 s-1) and 2,2,6,6-tetramethylpiperidine-N-oxyl (k1 = (2.1 ± 0.4) × 107 M-1 s-1) and absolute rate constants for nonrearranging radicals structurally related to 1. The mean value for k1) ((1.84 ± 0.4) × 107 M-1 s-1) should be used when 1 is employed as a tertiary alkyl free radical clock at ambient temperatures.
