Chandrashekar Ramarao

Polyurea-encapsulated palladium(ii) acetate: a robust and recyclable catalyst for use in conventional and supercritical mediaElectronic supplementary information (ESI) available: representative experimental procedures. See http://www.rsc.org/suppdata/cc/b2/b200677b/

Palladium(II) acetate microencapsulated in polyurea (MC-[Pd]) is an economical and versatile heterogeneous catalyst for a range of phosphine-free cross-coupling reactions in both conventional solvents and supercritical carbon dioxide (scCO2); the catalyst can be recovered by a simple filtration and recycled up to four times.

Palladium-containing perovskites: recoverable and reuseable catalysts for Suzuki couplingsElectronic supplementary information (ESI) available: experimental details. See http://www.rsc.org/suppdata/cc/b3/b308465e/

Palladium-containing perovskites (LaFe0.57Co0.38Pd0.05O3) have been exploited as recoverable and reuseable catalysts in Suzuki coupling reactions; residual levels of Pd after removal of the catalyst by filtration are low (2 ppm) despite evidence that the reaction is occurring via a homogeneous process.

Encapsulation of palladium in polyurea microcapsules

An interfacial polymerisation approach is adopted to encapsulate palladium(II) acetate and palladium nanoparticles in polyurea microcapsules for use in catalysis.

Transfer hydrogenation using recyclable polyurea-encapsulated palladium: efficient and chemoselective reduction of aryl ketones

A robust and recyclable palladium catalyst [Pd0EnCat] has been prepared by ligand exchange of polyurea-encapsulated palladium(II) acetate with formic acid, resulting in deposition of Pd(0) in the support material; Pd0EnCat is shown to be a highly efficient transfer hydrogenation catalyst for chemoselective reduction of a wide range of aryl ketones to benzyl alcohols.

Decarboxylative elimination of enol triflates as a general synthesis of acetylenes

Decarboxylative elimination of a range of enol triflates 11 of β-keto esters gives acetylenes 12.

Decarboxylative elimination of enol triflates as a general synthesis of acetylenesWe dedicate this paper to the memory of Dr John Harley-Mason, 1920?2003.

The enol trifluoromethanesulfonates 4, 8, 12, 17 and 20 of tert-butyl beta-ketodiesters and beta-ketoesters can be hydrolysed to the corresponding carboxylic acids by dissolution in trifluoroacetic acid. The dicarboxylic acids undergo mild decarboxylative elimination to give the acetylenic acids 4 and 9 in aqueous sodium bicarbonate solution at room temperature. Similarly, the monocarboxylic acids give the terminal and mid-chain acetylenes 13, 18, 21, and 24 by refluxing in acetone with potassium carbonate. One of the substituents on the acetylenes can be methyl, primary alkyl, secondary alkyl or ethynyl, and the other can be a carboxylic acid, hydrogen or primary alkyl, but the enol trifluoromethanesulfonates could not be prepared when one of the substituents was tert-butyl, nor when both substituents on the precursor to the acetylene were secondary alkyl.

An approach to open-chain 1,5-stereocontrol using a silyl group

Nucleophilic attack by an ethylcuprate on the α,β-unsaturated ketone 3 takes place anti to the silyl group to give largely (96∶4) a single product 4, fragmentation of which removes the silyl group, and reveals a pair of stereogenic centres having an open-chain 1,5 relationship 9.