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The rhodium-catalyzed controllable diverse arylation of 2,5-dihydrofuran with arylboronic acids is reported. By fine-tuning of the reaction conditions, four different ring-opening or oxidative aryl...

A chemodivergent synthesis of two series of spirochromans depending on the catalytic system was developed. Starting from diarylideneacetones and organoboronic acids, asymmetric rhodium catalysis le...

An expeditious synthetic route to 1,1-disubstituted indenes from propargyl alcohols and organoboronic acids was developed under rhodium catalysis, and selective 1,4-rhodium migration over β-oxygen elimination was involved as the key step. DPEphos was found to be crucial to promote the transformation, and density functional theory (DFT) calculations indicated that DPEPhos can lower the relative energy of the key intermediate on the 1,4-migration path, leading to the unusual selectivity.

An unprecedented rhodium-catalyzed homocoupling reaction of γ-alkylated tert-propargylic alcohols is reported, and 2-alkynylated buta-1,3-diene or 2-alkynylated hexa-1,3,5-triene are generated selectively. Multiple β-eliminations, including sequential β-carbon, β-hydrogen, and β-oxygen eliminations from the corresponding rhodium intermediates, are assumed to be involved during the reaction process.

For the purpose of revealing the promoting role of water on the reactivity of the supported Pt/FeOx catalyst in the low-temperature oxidation of CO, in situ diffuse reflectance infrared Fourier transform (DRIFT) spectra were conducted to study the adsorption properties of CO under various conditions. In the case of without water (CO + O-2), CO could be preferentially adsorbed on the active Pt sites, and then strongly adsorbed on the Fe3+ sites, which might considerably inhibit the ability for O-2 activation, and result in the decrease of reactivity of Pt/FeOx for low-temperature oxidation of CO. For the CO oxidation under wet condition (CO + O-2 + H2O), coadsorption of water and oxygen was observed, which could form surface oxygen/hydroxyls species, and significantly inhibit the adsorption of CO on the Fe3+ sites, thus avoiding the deep reduction of the active Fe3+ sites located at the boundaries between FeOx and Pt nanoparticles. In this case, the catalytic redox cycle in the active Fe3+ sites (mainly for O-2 activation) could be easily achieved by the addition of H2O, which finally results in the significant improvement of the activity and stability of the Pt/FeOx catalyst in low-temperature oxidation of CO.

A phosphine-catalyzed novel [4+2] annulation process was devised employing allene ketones as C2 synthons and β,γ-unsaturated α-keto esters as C4 synthons. In the presence of an L-threonine-derived bifunctional phosphine, 3,4-dihydropyrans were obtained in high yields and with virtually perfect enantioselectivities. The synthetic value of the dihydropyran motif was demonstrated by a concise preparation of an anti-hypercholesterolemic agent.

Phthalides were used for the first time in the allylic alkylation reactions with MBH carbonates for the creation of chiral 3,3-disubstituted phthalides. Highly enantioselective regiodivergent synthesis of γ-selective or β-selective allylic alkylation products was achieved by employing bifunctional chiral phosphines or multifunctional tertiary amine-thioureas as the catalyst, respectively. It was demonstrated that proper selection of catalysts and reaction conditions would differentiate an S(N)2'-S(N)2' pathway and an addition-elimination process, yielding different regioisomers of the allylic alkylation products in a highly enantiomerically pure form.

An efficient direct asymmetric aldol reaction between hydroxyacetone and β,γ-unsaturated α-keto esters has been successfully developed. In the presence of 9-amino-9-deoxy-epi-cinchonine and trifluoroacetic acid, the direct aldol reaction of O-protected hydroxyacetone proceeded in a highly enantioselective manner, affording the desired adducts containing a chiral tertiary alcohol in high yields and with excellent enantioselectivities. The aldol products obtained are valuable precursors for the synthesis of 2-substituted glycerol derivatives.