[Show abstract][Hide abstract] ABSTRACT: A Rh-catalyzed annulation of aryl thiocarbamates with internal alkynes via C-H bond activation has been developed. This protocol provides a new route to 3,4-disubstituted coumarins.
[Show abstract][Hide abstract] ABSTRACT: Spherical β-CD-silica hybrid materials have been prepared successfully by simple one-pot polymerization, which provide a new strategy to construct new type of HPLC chiral stationary phases. Various β-CD, ethane, triazinyl and 3,5-dimethylphenyl functional groups that can provide multiple interactions were introduced into the pore channels and pore wall framework of mesoporous materials, respectively. The materials towards some chiral, acidic, anilines and phenols compounds showed multiple chromatographic separation functions including racemic resolution, anion exchange and achiral separations with a typical feature of normal/reversed phase chromatography. Multi-tasking including racemic resolution and achiral separations for selected compounds were performed simultaneously on a chiral chromatographic column. The multifunctional character of materials arises from the multiple interactions including hydrophobic interaction, π-π interaction, anion exchange, inclusion interaction and hydrogen bonding interaction.
Journal of Chromatography A 01/2015; 1383:70–78. DOI:10.1016/j.chroma.2015.01.023 · 4.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: A direct synthesis of polysubstituted olefins via construction of CC bonds, which involves the direct dehydrative coupling of alcohols or alkenes with alcohols, was realized using a series of alkanesulfonic acid group‐functionalized ionic liquids (SO3H‐functionlization ILs) without additives. The metal‐free and recyclable catalyst system avoided the disposal and neutralization of acidic catalysts after reaction and tolerated a broad range of substrates, including benzylic, allyl, propargylic, aliphatic and aromatic or aliphatic olefins. Additionally, the catalytic system was suitable for a gram‐scale preparation. Preliminary mechanistic studies indicated that the CH bond cleavage in this reaction might be involved in the rate‐determining step.
[Show abstract][Hide abstract] ABSTRACT: The nucleophilic addition of thiocarbamate imidazolium ylide to aldehyde triggered sequential intramolecular N to O migration of thiocarbonyl amide group and reversible oxygen-sulfur rearrangement to afford 2-imidazolium alkylcarbamothioate. The ortho group on phenyl of aldehyde strongly affects the balance of the O- to S-rearrangement.
[Show abstract][Hide abstract] ABSTRACT: AbstractA series of sulfonic acid‐functionalized (SO3H‐functionalized) ionic liquids was synthesized and used as metal‐free, highly selective and efficient catalysts for the direct amination of alcohols. Notably, the activities of the series of SO3H‐functionalized ionic liquids were compared and a 92% isolated yield was obtained using 3‐tetradecyl‐1‐(butyl‐4‐ sulfonyl)imidazolium trifluoromethanesulfonate ([BsTdIM][OTf]) as the catalyst. Importantly, the catalytic system has wide substrate scope including benzylic, allyl, propargylic, aliphatic alcohols with sulfonamide, amide, carbamate, aromatic amine and N‐heterocyclic compounds. Interestingly, the system was also suitable for a multi‐gram scale direct amination of alcohols. Additionally, the reusable nature of [BsTdIM][OTf] makes this protocol more attractive and avoids the disposal and neutralization of acidic catalysts. Moreover, preliminary experiments indicated that this reaction should proceed via an SN1 pathway.
[Show abstract][Hide abstract] ABSTRACT: A series of acidic-functionalized ionic liquids were synthesized and applied to the hetero-Michael addition of nitrogen, sulfur and oxygen nucleophiles to α,β-unsaturated ketones under solvent-free conditions. Notably, 1-methylimidazolium p-toluenesulfonic ([Hmim]OTs) was found to be the most efficient catalyst and could realize "homogeneous catalysis, two-phase separation". Additionally, the catalytic system has wide substrate scope and good to excellent yields (up to 99%) could be obtained at room temperature.