Silica-Supported Cationic Gold(I) Complexes as Heterogeneous Catalysts for Regio- and Enantioselective Lactonization Reactions

Shu, Xing‐Zhong; Nguyen, Son C.; He, Ying; Oba, Fadekemi; Zhang, Qiao; Canlas, Christian G.; Somorjai, Gábor A.; Alivisatos, A. Paul; Toste, F. Dean

doi:10.1021/jacs.5b04294

Cited by 112 publications

(64 citation statements)

References 48 publications

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“…reported the heterogenisation of the gold complex [Tf 2 NAuPPh 3 CH 2 NH 2 ] and new pyrene‐tagged gold complexes . A cationic Au I complex with a BF 4 moiety was reported by Somorjai's and Toste's groups, while other authors reported heterogenisation of Au I –carbene compounds . Immobilisation of a Au III –bipy complex was also reported by Yang et al .…”

Section: Introductionmentioning

confidence: 99%

Commercial Gold(I) and Gold(III) Compounds Supported on Carbon Materials as Greener Catalysts for the Oxidation of Alkanes and Alcohols

et al. 2018

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Strategies are presented for single‐pot efficient oxidative functionalization of cyclohexane and alcohols, under mild conditions, catalysed by Au(I) or Au(III) compounds supported on different carbon materials with three different surface treatments. The obtained materials were tested for the oxidation of cyclohexane under mild conditions (room temperature and atmospheric pressure), using an environmentally friendly oxidant (tert‐butyl hydroperoxide, TBHP, 70 % aqueous solution). All materials were very selective to the production of cyclohexanol and cyclohexanone with no trace of by‐products detected. The catalysts were also tested in the selective oxidation of methyl benzyl alcohol, cyclohexanol, and 2‐octanol with TBHP, under microwave irradiation, to the corresponding aldehydes or ketones. In general, better results are obtained for the heterogenised complexes and that the most efficient support is CNT‐ox‐Na. This is the first report on the oxidation of C−H bonds using the mononuclear gold complexes used; only the oxidation of unsaturated units had been reported previously. The sp3‐C−H activation is much more difficult than the oxidation of unsaturated molecules with molecular oxidants.

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Section: Introductionmentioning

confidence: 99%

Commercial Gold(I) and Gold(III) Compounds Supported on Carbon Materials as Greener Catalysts for the Oxidation of Alkanes and Alcohols

et al. 2018

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“…Silica nanostructures have been successfully applied as support for heterogeneous catalyst [1,2], as filler for strengthening concrete and structural composites [3,4], as a stable, non-toxic platform for biomedical applications in drug delivery and theranostics [5,6], and as an additive in rubbers and plastics [7,8]. Moreover, an increased scientific interest has recently evolved around silica nanostructures for multifunctional, nanometer-scale containers for controlled release of fertilizers [9], pesticides [10], and biocides [11].…”

Section: Introductionmentioning

confidence: 99%

Biogenic SiO2 in colloidal dispersions via ball milling and ultrasonication

2016

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“…More recently, Toste, Alivisatos, Somorjai, and co‐workers developed a type of silica‐supported chiral cationic gold(I) complex as a heterogeneous catalyst and applied it in the intramolecular enantioselective hydrocarboxylation of allenoic acids . The heterogeneous gold catalyst SBA‐15@[( R )‐dm‐MeObiphep(AuBF 4 ) 2 ] was readily accessed by simply stirring mesoporous silica SBA‐15 with [( R )‐dm‐MeObiphep(AuBF 4 ) 2 ] in CH 2 Cl 2 solution at room temperature, separating by centrifugation, washing with CH 2 Cl 2 , and drying under vacuum.…”

Section: Cyclization Of C−c Multiple Bonds With Tethered Nucleophilesmentioning

confidence: 99%

Gold‐Catalyzed Enantioselective Annulations

Zhang

2016

Chemistry A European J

214

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Non-oxidative,regioselective,and convergent access to densely functionalized oxazoles is realized in af unctional-group tolerant manner using alkynyl thioethers.S ulfur-terminated alkynes provideaccess to reactivity previously requiring strong donor-substituted alkynes such as ynamides.Sulfur does not act in an analogous donor fashion in this gold-catalyzed reaction, thus leading to complementary regioselective outcomes and addressing the limitations of using ynamides. Compared to other heteroatom-substituted alkynes,alkynyl thioethers are remarkably little explored in intermolecular late-transition-metal catalysis,d espite being readily accessed and robust. [1, 2] Ynamides,i nc ontrast, are privileged sub-strates:i np-acid catalysis their donor nature aids metal-alkyne coordination and affords highly polarized electro-philes,t hus providing the high chemo-and regioselectivity required for the discovery of efficient intermolecular reactions (Scheme 1a). [3,4] As the resulting inclusion of ad onor-nitrogen atom limits the utility of the products,r etaining the reactivity profile of these transformations whilst accessing more flexible and readily elaborated substitution patterns would be desirable.T he value of sulfur-substituted compounds [5] coupled with progress in C À Ca nd C-heteroatom bond formation from CÀSbonds, [6] renders alkynyl thioethers appealing alternatives to ynamides.I ndeed the ketenethio-nium pathway (Scheme 1a)f rom alkynyl thioethers has recently been invoked in proton-catalyzed reactions with nitriles [2g,h] and gold-catalyzed reactions with sulfides. [2i] Ynamides enabled the discovery of formal [3+ +2] dipolar cycloadditions with nucleophilic nitrenoids, [7] thus allowing intermolecular access to a-imino gold carbene-type reactivity for heterocycle synthesis (Scheme 1b). [8, 9] Such reactions, which do not depend on ynamides,a re scarce. [8b,h] As trong donor alkyne substituent proved critical in the formation of oxazoles using N-acyl pyridinium N-aminides,aselectron-rich alkynes such as anisole derivatives did not react (Scheme 1b, inset). [8a,b] Oxazoles are valuable synthetic intermediates [10,11] and structural components in bioactive natural products, [12] agrochemicals, [13] ligands, [14] and functional materials. [15] Despite recent advances,asingle modular and convergent route to trisubstituted oxazoles,which provides the structural and functional-group diversity needed across the 2-, 4-, and 5-positions,r emains unrealized. [16] Following our interest in the use of gold catalysis with sulfides [17] we report here on the reactivity of alkynyl thioethers with nucleophilic nitrenoids to prepare oxazoles. Importantly,t he regioselectivity is not consistent with ac on-trolling ketenethionium species.T he sulfur group plays an alternative role in enabling reactivity,t hus proving complementary to donor-enabled approaches. Ther eaction of the alkynyl thioether 1a and aminide 2a (Table 1) showed that conversion into the oxazole 3 was possible at 125 8 8Ci n1 ,2-dichlorobenzene (1,2-DCB;s ...

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Silica-Supported Cationic Gold(I) Complexes as Heterogeneous Catalysts for Regio- and Enantioselective Lactonization Reactions

Cited by 112 publications

References 48 publications

Commercial Gold(I) and Gold(III) Compounds Supported on Carbon Materials as Greener Catalysts for the Oxidation of Alkanes and Alcohols

Commercial Gold(I) and Gold(III) Compounds Supported on Carbon Materials as Greener Catalysts for the Oxidation of Alkanes and Alcohols

Biogenic SiO2 in colloidal dispersions via ball milling and ultrasonication

Gold‐Catalyzed Enantioselective Annulations

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