A micro-environment tuning approach for enhancing the catalytic capabilities of lanthanide containing polyoxometalate in the cyanosilylation of ketones.

The as-synthesized (TBA)8H5[Nd(SiW11O39)2] manifested high catalytic activity for cyanosilylation of ketones, and its catalytic activity could be improved further through rational design of the reaction micro-environment beyond the molecular level, and the corresponding mechanism has been systematically studied.

The role of urinary renalase on early-stage renal damage in Chinese adults with primary hypertension.

Unlabelled: It would be of great clinical value to find an indicator that can accurately evaluate the early-stage renal injury in primary hypertension. Previous findings have shown renalase not only plays an important role in hypertension but also closely correlates with kidney function. The purpose of this study is to investigate whether urinary renalase could be used as a predictive index of early-stage renal damage in patients with primary hypertension.

Gold-catalyzed asymmetric allylic substitution of free alcohols: an enantioselective approach to chiral chromans with quaternary stereocenters for the synthesis of vitamin E and analogues.

The enantioselective synthesis of α- and γ-tocopherol (the most biologically active members of vitamin E family) and analogues has been accomplished employing a new enantioselective gold catalyzed intramolecular allylic alkylation reaction followed by an olefin cross-metathesis as key steps. The methodology proved to be applicable to different olefins highlighting its potential for the synthesis of diverse libraries.

Chiral organic contact ion pairs in metal-free catalytic asymmetric allylic substitutions.

Chiral contact ion-pair catalysis with particular focus on metal-free processes is gaining in interest. As a result, new perspectives are opened, and highly stereoselective transformations, traditionally performed under metal catalysis, can be realized. Herein, we report the development of an unprecedented asymmetric Brønsted acid-catalyzed allylic alkylation.

Regiocontrolled synthesis of ethene-bridged para-phenylene oligomers based on Pt(II)- and Ru(II)-catalyzed aromatization.

We report the regiocontrolled syntheses of ethene-bridged para-phenylene oligomers in three distinct classes by using Pt(II)- and Ru(II)-catalyzed aromatization. This synthetic approach has been developed based on twofold aromatization of the 1-aryl-2-alkynylbenzene functionality, which proceeds by distinct regioselectivity for platinum and ruthenium catalysts. Variable-temperature NMR spectra provide evidence that large arrays of these oligomers are prone to twist from planarity.

The skeletal rearrangement of gold- and platinum-catalyzed cycloisomerization of cis-4,6-dien-1-yn-3-ols: pinacol rearrangement and formation of bicyclo[4.1.0]heptenone and reorganized styrene derivatives.

With gold and platinum catalysts, cis-4,6-dien-1-yn-3-ols undergo cycloisomerizations that enable structural reorganization of cyclized products chemoselectively. The AuCl3-catalyzed cyclizations of 6-substituted cis-4,6-dien-1-yn-3-ols proceeded via a 6-exo-dig pathway to give allyl cations, which subsequently undergo a pinacol rearrangement to produce reorganized cyclopentenyl aldehyde products. Using chiral alcohol substrates, such cyclizations proceed with reasonable chirality transfer.

Metal-catalyzed cycloisomerization of enyne functionalities via a 1,3-alkylidene migration.

We report a new metal-catalyzed 6-endo-dig cyclization of cis-4,6-dien-1-yn-3-ols, which produces substituted benzene and naphthalene derivatives with structural reorganization. In this process, we observe a 1,3-alkylidene migration via cleavage of the olefin double bond of the starting substrates. The ease and reliability of this cyclization are manifested by its compatibility with a wide array of diverse substrates and several pi-alkyne activators, including PtCl2, Zn(OTf)2, AuCl, and AuCl3.

Solvent-dependent chemoselectivity in ruthenium-catalyzed cyclization of iodoalkyne-epoxide functionalities.

[reaction: see text] Treatment of 1-(2'-iodoethynylphenyl)-2-propyloxirane (3) with TpRuPPh(3)(CH(3)CN)(2)PF(6) catalyst (10 mol %) produced 1-iodo-2-naphthol (3a) exclusively in DMF, but gave 2-iodobenzo[d]oxepin (3b) efficiently in benzene. Such a solvent-dependent chemoselectivity suggests a solution equilibrium between ruthenium-pi-iodoalkyne and ruthenium-2-iodovinylidene intermediates.

Ruthenium-catalyzed cyclization of alkyne-epoxide functionalities through alternation of the substituent and structural skeleton of epoxides.

Treatment of 1-(o-ethynylphenyl)-2-alkyl-2-aryl epoxides with TpRuPPh(3)(CH(3)CN)(2)PF(6) catalyst (10 mol %) in hot toluene (100 degrees C, 12 h) led to an atypical cyclization and gave 1-aryl-2-alkyl-1H-indene derivatives and carbon monoxide efficiently. The cyclization of 1-cis-enynyl-2-alkyl epoxides with this catalyst in hot toluene (10 mol %, 100 degrees C, 12 h) gave 2,5-disubstituted phenols in 45-72% yields. Under the same conditions, 1-cis-enynyl- 2,2-dialkyl epoxides and 1-cis-enynyl- 2-alkyl-2-aryl epoxides gave the corresponding 6,6-disubstituted cyclohexa-2,4-dien-1-ones in good yields (85-91%).

Ruthenium-catalyzed cyclization of epoxide with a tethered alkyne: formation of ketene intermediates via oxygen transfer from epoxides to terminal alkynes.

Treatment of (o-ethynyl)phenyl epoxides with TpRuPPh(3)(CH(3)CN)(2)PF(6) (10 mol %) in hot toluene (100 degrees C, 3-6 h) gave 2-naphthols or 1-alkylidene-2-indanones very selectively with isolated yields exceeding 72%, depending on the nature of the epoxide substituents. Surprisingly, the reaction intermediate proved to be a ruthenium-pi-ketene species that can be trapped efficiently by alcohol to give an ester compound. This phenomenon indicates a novel oxygen transfer from epoxide to its terminal alkyne catalyzed by a ruthenium complex.