24794-19-2Relevant academic research and scientific papers
Zur Koordination Mehrfunktioneller Thioether in Cyclopentadienyleisen-Komplexen
Kuhn, Norbert,Schumann, Hans
, p. 93 - 104 (1986)
+ reacts with the ligands L-L and L-L-L to give the cations + (L-L= RS(CH2)nSR, 1,4-dithiane) and + (L-L-L= 1,3,5-trithiane, tris(methylmercapto)methane) containing monodentate coordinated sulfur ligands.In a similar way, sulfur ligand bridged dinuclear dications 2+ and 2+ and trinuclear trications 3+ are formed.Irradiation of the mononuclear cations gives the chelate complexes 2-L-L)>+.
A Bulky Disulfoxide Ligand for Pd-Catalyzed Oxidative Allylic C-H Amination with 2,2,2-Trichloroethyl Tosyl Carbamate
Li, You-Gui,Li, Li,Yang, Ming-Yue,He, Gang,Kantchev, Eric Assen B.
, p. 4907 - 4917 (2017/05/12)
Challenging substrates and conditions in homogeneous catalysis pose stringent demands on the ligands used. A novel, bulky, 1-adamantyl-substituted disulfoxide ligand designed after a systematic evaluation of the electronic and steric properties of disulfoxide substituents permits the allylic oxidative C-N coupling reaction to proceed at lower catalyst loading while requiring a smaller excess of reagents. Additionally, this ligand improves the yields when TsNHCOOCH2CCl3, a novel reagent that permits deprotection of the products under both acidic and basic conditions, is used.
A highly efficient heterogeneous rhodium(I)-catalyzed C-S coupling reaction of thiols with polychloroalkanes or alkyl halides under mild conditions
Xia, Jianhui,Yao, Ruiya,Cai, Mingzhong
, p. 221 - 225 (2015/03/30)
Heterogeneous C-S coupling reaction of thiols with polychloroalkanes or alkyl halides was achieved at 30 or 80 °C in the presence of 5 mol% of an MCM-41-immobilized bidentate phosphine rhodium complex (MCM-41-2P-RhCl(PPh3)) and triethylamine, yielding a variety of formaldehyde dithioacetals, ethylenedithioethers and unsymmetric thioethers in good to excellent yields. This heterogeneous rhodium catalyst can be easily recovered and recycled by simple filtration of the reaction solution and used for at least 10 consecutive trials without significant loss of activity.
Molecular complexity via C-H activation: A dehydrogenative Diels-Alder reaction
Stang, Erik M.,White, M. Christina
supporting information; experimental part, p. 14892 - 14895 (2011/11/01)
Traditionally, C-H oxidation reactions install oxidized functionality onto a preformed molecular skeleton, resulting in a local molecular change. The use of C-H activation chemistry to construct complex molecular scaffolds is a new area with tremendous potential in synthesis. We report a Pd(II)/bis-sulfoxide- catalyzed dehydrogenative Diels-Alder reaction that converts simple terminal olefins into complex cycloadducts in a single operation.
Allylic C-H alkylation of unactivated α-olefins: Serial ligand catalysis resumed
Young, Andrew J.,White, M. Christina
supporting information; scheme or table, p. 6824 - 6827 (2011/09/19)
A delicate interplay of several kinetically labile ligands is required for reactions that proceed through serial ligand catalysis mechanisms. An investigation of the disruption of this balance has enabled the development of a method for the intermolecular
Silica-promoted facile synthesis of thioesters and thioethers: A highly efficient, reusable and environmentally safe solid support
Basu, Basudeb,Paul, Susmita,Nanda, Ashis K.
experimental part, p. 767 - 771 (2010/09/05)
An efficient, mild and rapid procedure for the acylation and alkylation of aromatic and aliphatic thiols mediated on a silica gel surface at room temperature is described. The protocol allows the protection of thiols under neutral heterogeneous conditions without requiring any bases or Lewis acids, and the silica gel used as the promoter can be recycled for several runs without any loss of activity.
Novel dithioether-silver(I) coordination architectures: Structural diversities by varying the spacers and terminal groups of ligands
Li, Jian-Rong,Ba, Xian-He,Jiao, Jiao,Du, Wen-Ping,Xu, Xiu-Hua,Zhang, Ruo-Hua
, p. 464 - 474 (2007/10/03)
An investigation into the dependence of the framework formation of coordination architectures on ligand spacers and terminal groups was reported based on the self-assembly of AgClO4 and eight structurally related flexible dithioether ligands, RS(CH2)nSR (L an, R = ethyl group, Lbn, R = benzyl group, n = 1-4). Eight novel metal-organic architectures, [Ag(L a1)3/2ClO4]n (1a), [Ag2(La2)2(ClO4) 2]2 (2a), [AgLa3ClO 4]n (3a), {[Ag(La4) 2]ClO4}n (4a), [AgLb 1ClO4]2 (1b), [Ag(Lb 2)2]ClO4 (2b), {[Ag(Lb 3)3/2(ClO4)1/2](ClO 4)1/2}n(3b) and [Ag(Lb 4)3/2ClO4]n (4b), were synthesized and structurally characterized by X-ray crystallography. Structure diversities were observed for these complexes: 1a forms a 2-D (6,3) net, while 2a is a discrete tetranuclear complex, in which the Ag1 ion adopts linear and tetrahedral coordination modes, and the S donors in each ligand show monodentate terminal and μ2-S bridging coordination fashions; 3a has a chiral helical chain structure in which two homo-chiral right-handed single helical chains (Ag-La3-)n are bound together through μ2-S donors, and simultaneously gives rise to left-handed helical entity (Ag-S-)n. In 4a, left- and right-handed helical chains formed by the ligands bridging Ag1 centers are further linked alternately by single-bridging ligands to form a non-chiral 2-D framework. 1b has a dinuclear structure showing obvious ligand-sustained Ag Ag interaction, while 2b is a mononuclear complex; 3b is a 3-D framework formed by ClO4- linking the 2-D (6,3) framework, which is similar to that of 1a, and 4b has a single, double-bridging chain structure in which 14-membered dinuclear ring units formed through two ligands bridging two Ag 1 ions are further linked by single-bridging ligands. In addition, a systematic structural comparison of these complexes and other reported AgClO4, complexes of analogous dithioether ligands indicates that the ligand spacers and terminal groups take essential roles on the framework formation of the Ag1 complexes, and this present feasible ways for adjusting the structures of such complexes by modifying the ligand spacers and terminal groups.
A Sulfoxide-Promoted, Catalytic Method for the Regioselective Synthesis of Allylic Acetates from Monosubstituted Olefins via C-H Oxidation
Chen, Mark S.,White, M. Christina
, p. 1346 - 1347 (2007/10/03)
Sulfoxide ligation to Pd(II) salts is shown to selectively promote C-H oxidation versus Wacker oxidation chemistry and to control the regioselectivity in the C-H oxidation products. A catalytic method for the direct C-H oxidation of monosubstituted olefins to linear (E)-allylic acetates in high regio- and stereoselectivities and preparatively useful yields is described. The method using benzoquinone as the stoichiometric oxidant and 10 mol % of Pd(OAc)2 or Pd(O2CCF3)2 as the catalyst in a DMSO/AcOH (1:1) solution was found to be compatible with a wide range of functionality (e.g., amides, carbamates, esters, and ethers, see Table 2). Addition of DMSO was found to be critical for promoting the C-H oxidation pathway, with AcOH alone or in combination with a diverse range of dielectric media, leading to mixtures favoring Wacker-type oxidation products (Tables 1, S3). To explore the role of DMSO as a ligand, the bis-sulfoxide Pd(OAc)2 complex 1 was formed and found to be an effective C-H oxidation catalyst in the absence of DMSO (eqs 2, 3). Moreover, catalyst 1 effects a reversal of regioselectivity, favoring the formation of branched allylic acetates. Copyright
Studies in the Cycloproparene Series: Reactions with Radicals
Chai, Christina L. L.,Christen, Detlev,Halton, Brian,Neidlein, Richard,Starr, Malcolm A. E.
, p. 577 - 592 (2007/10/02)
The behaviour of 1H-cyclopropabenzene (1) and 1H-cyclopropanaphthalene (23) towards a variety of radicals results in opening of the three-membered ring to give ortho-substituted benzyl and 2-methylnaphthalene derivatives, e.g. (13) and (28), respectively.Ring expansion into the cycloheptatriene manifold by way of addition to the bridge bond and norcaradiene formation have not been observed.Analogous reactions with the methylidenecyclopropanaphthalenes (33) and (34) lead to much decomposition, and provide little evidence for the C 1 cycloproparenyl radicals (35) and (36).
