Highly efficient tetrahydropyranylation of alcohols and phenols catalyzed by a new and reusable high-valent vanadium(IV) porphyrin

In the present work, the catalytic activity of high-valent tetraphenylporphyrinatovanadium(IV) trifluoromethanesulfonate, [V^IV(TPP)(OTf)₂], in the tetrahydropyranylation of alcohols and phenols with 3,4-dihydro-2H-pyran (DHP) is reported. This new electron-deficient V(IV) compound was used as a highly efficient catalyst for pyranylation of primary (aliphatic and benzylic), sterically-hindered secondary and tertiary alcohols with DHP. Tetrahydropyranylation of phenols with DHP was also performed to afford the desired THP-ethers. The chemoselectivity of this method was also investigated. The results indicated that primary alcohols are more reactive in the presence of secondary and tertiary alcohols and phenols. This catalyst was reused several times without loss of its activity.     

Rapid,highly efficient and chemoselective trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) catalyzed by reusable electron‐deficient tin(IV)porphyrin

In this paper, rapid and highly efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) in the presence of catalytic amounts of high‐valent [Sn^IV(TPP)(OTf)₂] is reported. This catalytic system catalyzes trimethylsilylation of primary, secondary and tertiary alcohols as well as phenols, and the corresponding TMS‐ethers were obtained in high yields and short reaction times at room temperature. It is noteworthy that this method can be used for chemoselective silylation of primary alcohols in the presence of secondary and tertiary alcohols and phenols. The catalyst was reused several times without loss of its catalytic activity. Copyright © 2009 John Wiley & Sons, Ltd.     

Rapid and efficient ring opening of epoxides catalyzed by a new electron deficient tin(IV) porphyrin

The new electron deficient tin(IV) tetraphenylporphyrinato trifluoromethanesulfonate, [Sn^IV(tpp)(OTf)₂], was used as an efficient catalyst for the alcoholysis, hydrolysis and acetolysis of epoxides. Conversion of epoxides to thiiranes and acetonides were also performed efficiently in the presence of this catalyst.     

Polystyrene-bound electron-deficient tin(IV) porphyrin: A new, highly efficient, robust and reusable catalyst for acetylation of alcohols and phenols with acetic anhydride

In the present work, tetrakis(p-aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [Sn^IV(TNH₂PP)(OTf)₂], supported on chloromethylated polystyrene was prepared and characterized by elemental analysis, FT IR and diffuse reflectance UV-Vis spectroscopic methods. This new heterogenized catalyst was used for acetylation of alcohols and phenols with acetic anhydride in short reaction times and high yields. The catalyst is of high reusability and stability in the acetylation reactions and was recovered several times without loss of its initial activity and catalyst leaching.     

Facile formation of a meso-meso linked porphyrin dimer catalyzed by a manganese(IV)-oxo porphyrin

A manganese(IV)-oxo porphyrin catalyzes C-C bond formation between zinc porphyrins at the meso-position with a two-electron oxidant to afford the meso-meso linked porphyrin dimer efficiently. The meso-meso linked dimer is formed via formation of the porphyrin radical cation, and the rate-determining step in the catalytic cycle is the formation of a manganese(IV)-oxo porphyrin with a two-electron oxidant.     

Highly efficient protection of alcohols and phenols catalysed by tin porphyrin supported on MIL‐101

The catalytic activity of 5,10,15,20‐tetrakis(4‐aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [Sn^IV(TNH₂PP)(OTf)₂], supported on chloromethylated MIL‐101, was investigated in the trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and also their tetrahydropyranylation with 3,4‐dihydro‐2H‐pyran. Excellent yields, mild reaction conditions, short reaction times and reusability of the catalyst without significant decrease in its initial activity are noteworthy advantages of this supported catalyst. Copyright © 2015 John Wiley & Sons, Ltd.     

Graphene oxide‐bound electron‐deficient tin(IV) porphyrin: a highly efficient and selective catalyst for trimethylsilylation of alcohols and phenols with hexamethyldisilazane

The catalytic activity of graphene oxide‐bound tetrakis(p ‐aminophenyl)porphyrinatotin(IV) trifluoromethanesulfonate, [Sn^IV(TNH₂PP)(OTf)₂], in the trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) is reported. The prepared catalyst was characterized using inductively coupled plasma analysis, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared and diffuse reflectance UV–visible spectroscopies. This heterogeneous catalyst was used for selective trimethylsilylation of various alcohols and phenols with HMDS in short reaction times and high yields. Also, the catalyst is of high reusability and stability, in that it was recovered several times without loss of its initial activity. The chemoselectivity of this catalytic system in the silylation of primary alcohols in the presence of secondary and tertiary alcohols and also phenols was investigated.     

Deoxygenation of tertiary and secondary benzylic alcohols into alkanes with triethylsilane catalyzed by solid acid tin(IV) ion-exchanged montmorillonite

We discovered an efficient protocol for the conversion of tertiary and secondary benzylic alcohols into the corresponding alkanes in good to quantitative yields by employing tin(IV) ion-exchanged montmorillonite (Sn-Mont) as a solid acid catalyst and Et3SiH as the hydride source. The reaction is likely to proceed via the S_N1-type reaction mechanism, that is, the formation of carbenium ions, followed by the addition of a hydride from the silane. The work-up of the reaction only requires simple filtration of the solid acid without any neutralization of the acid catalyst.     

Gal3 Catalyzed Tetrahydropyranylation of Alcohols and Phenols

In dichloromethane, the nucleophilic addition of alcohols or phenols to 3,4-dihydro-2H-pyran (DHP) was catalyzed effectively by gallium triiodide which was generated in situ by the reaction of gallium metal and iodine to give the corresponding tetrahydropyranyl acetals in good to excellent yields.     

对氨基苯磺酸铜/乙酸催化醇和酚的四氢吡喃化反应(英文)

考察了对氨基苯磺酸盐(铜、镍、锌、钴、铝、镉、锰、镧、亚钸、谱、钕、钐、铕、铽、镝、钬、铒)和布朗斯特酸在醇和酚的四氢吡喃化反应中的协同催化效应.其中,对氨基苯磺酸铜与乙酸的协同催化效果最好.室温无溶剂条件下,各种醇和酚的四氢吡喃化反应产率均较高.反应结束后,对氨基苯磺酸铜重复使用6次,催化活性无明显下降.     

A tin(IV)-ruthenium(II)-tin(IV) cyclic porphyrin trimer with replaceable chiral linings

A series of cyclic metalloporphyrin trimers, Ru(CO)(py)[Sn(carboxylate)2](2)2, having cavities lined with different carboxylate groups are synthesized by adding the appropriate carboxylic acids to the mixed trimer Ru(CO)(py)-[Sn(OH)2](2)2. This methodology provides ready access to a wide range of cavities lined with substituents possessing chirality or hydrogen-bonding groups. The potential of such systems is illustrated by synergistic binding of a hydroxypyridine to the Ru(II)-CO center and to the hydroxyl groups of a D-quinate-lined cavity. The effect of changing the carboxylate lining of the cavity on the course of epoxidation reactions catalyzed by these trimers is also reported.     

A thermal synthesis of a new tin(IV) dithiocarbamate

A new tin dithiocarbamate containing sulphur bridges, di--sulphidobis [bis(N,N-diethyldithiocarbamato)tin(IV)], has been isolated from the thermal decomposition of tetrakis(N,N-diethyldithiocarbamato)tin(IV). A dimeric structure is proposed on the basis of results from mass spectrometry, infrared spectroscopy, thermal analysis and vapour pressure osmometry.

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Zusammenfassung Ein neues, Schwefelbrücken enthaltendes Zinn-Dithiocarbamat, Di--sulfidobis[bis(N,N-diäthyldithiocarbamato)Zinn(IV)], wurde bei der Zersetzung von Tetrakis(N,N-diäthyl-dithiocarbamato)Zinn(IV) isoliert. Aufgrund der Ergebnisse der Massenspektrometrie, der Infrarotspektroskopie, der Thermoanalyse und der Dampfdruck-Osmometrie wird eine Dimerstruktur vorgeschlagen.

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Résumé Un nouveau dithiocarbamate d'étain contenant des ponts de soufre, le di--sulfidobis[bis(N,N-diéthyl-dithiocarbamato)é tain(IV)], a été isolé lors de la décomposition thermique du tétrakis(N,N-diethyl-dithiocarbamato) étain(IV). Une structure dimère est proposéeà partir des résultats obtenus par spectrométrie de masse, spectroscopie infrarouge, analyse thermique et osmométrie sous pression de vapeur.

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—-- [/N,N- (/IV)], [/N,N- (/IV)], , (N,N- ) (IV). - , , .

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The authors gratefully acknowledge the assistance given by Dr. A. G. Wedd with the vacuum sublimation technique. One of us, G. K. B., is grateful for a research scholarship provided by La Trobe University.     

Cycloaddition of epoxide and CO2 to cyclic carbonate catalyzed by VO(IV) porphyrin

The cycloaddition of epoxide and CO₂ to synthesize cyclic carbonate catalyzed by VO(IV) porphyrin was achieved under 1.4 MPa at 150°C. The effects of reaction temperature, time, CO₂ pressure, co‐catalyst and porphyrin framework were investigated. The catalytic results showed that moderate to high yields of cyclic carbonates were obtained under the optimal reaction conditions. Copyright © 2015 John Wiley & Sons, Ltd.     

Enantioselective alkynylation of aldehydes catalyzed by a camphor sulfonylated amino alcohols titanium(IV) catalyst system

A new titanium(IV) complex has been developed for the effective enantioselective alkynylation of phenylacetylene addition to aldehydes. The titanium(IV) complex was readily prepared in situ from (R)‐C‐(7,7‐dimethyl‐2‐oxo‐bicyclo[2.2.1]hept‐1‐yl)‐(1R,2S)‐N‐(2‐hydroxy‐1,2‐diphenyl‐ethyl)‐methanesulfonamide (1h) and tetraisopropyl titanate [Ti(i‐OPr)₄]. A variety of aromatic aldehydes and α,β‐unsaturated aldehydes were found to be suitable substrates in the presence of the camphor sulfonylated amino alcohol titanium(IV) complex [10 mol% 1h, 40 mol% Ti(i‐OPr)₄]. The desired propargylic alcohols were afforded with high isolated yields (up to 90%) and moderate enantioselectivities (up to 65% ee) under mild conditions. Copyright © 2010 John Wiley & Sons, Ltd.     

Ruthenium(III) chloride catalyzed acylation of alcohols, phenols, thiols, and amines

Ruthenium(III) chloride catalyzes the acylation of a variety of phenols, alcohols, thiols, and amines under mild conditions. Some of the major advantages of this method are high yields, short reaction times, ease of operation, and compatibility with other protecting groups.     

Ruthenium(IV) porphyrin catalyzed phosphoramidation of aldehydes with phosphoryl azides as a nitrene source

[Ru(IV)(por)Cl(2)] (por = porphyrin dianion) can efficiently catalyze nitrene insertion into aldehyde C-H bonds with phosphoryl azides as a nitrene source to give N-acylphosphoramidates in good to high yields.     

Zinc triflate catalyzed acylation of alcohols,phenols, and thiophenols

An expedient procedure for the acylation of alcohols, phenols, and thiophenols using catalytic amount of Zn(OTf)₂ is described. This procedure is highly suitable for industrial application due to use of less toxic metal as a part of catalyst, short reaction time at ambient temperature, without any racemization of chiral alcohols.     

Poly(4-vinylpyridine) catalyzed chemoselective O-TMS protection of alcohols and phenols and N-Boc protection of amines

Poly(4-vinylpyridine) (PVP) acts as an efficient and reusable catalyst for the selective and efficient trimethylsilylation of alcohols and phenols with hexamethyldisilazane (HMDS) and N-tert-butoxycarbonylation of amines with (Boc)₂O. All reactions were performed under mild conditions in good to high yields.