No abstract

Here we report ap alladium-catalysed difunctionalisation of unsaturated CÀCb onds with acid chlorides.F ormally,t he C À COCl bond of an acid chloride is cleaved and added, with complete atom economy,a cross either strained alkenes or atethered alkyne to generate new acid chlorides.The transformation does not require exogenous carbon monoxide, operates under mild conditions,shows agood functional group tolerance,a nd gives the isolated products with excellent stereoselectivity.T he intermolecular reaction tolerates both aryl-and alkenyl-substituted acid chlorides and is successful when carboxylic acids are transformed to the acid chloride in situ. The reaction also shows an example of temperaturedependent stereodivergence which,t ogether with plausible mechanistic pathways, is investigated by DFT calculations. Moreover,w es how that benzofurans can be formed in an intramolecular variant of the reaction. Finally,derivatisation of the products from the intermolecular reaction provides ahighly stereoselective approach for the synthesis of tetrasubstituted cyclopentanes.

Tetracationic cyclo-tetraphosphane [(LC)4P4]4+ as triflate salt (LC = 4,5-dimethyl-1,3-diisopropyl-imidazol-2-yl) is obtained from the reduction of [LCPCl2]+ with 1,4-bis(trimethylsilyl)-1,4-dihydropyrazine and represents the first salt of the cationic cyclo-phosphane series with the general formula [LnPn]n+.

An efficient palladium‐catalyzed chlorocarbonylation of aryl (pseudo)halides that gives access to a wide range of carboxylic acid derivatives has been developed. The use of butyryl chloride as a combined CO and Cl source eludes the need for toxic, gaseous carbon monoxide, thus facilitating the synthesis of high‐value products from readily available aryl (pseudo)halides. The combination of palladium(0), Xantphos, and an amine base is essential to promote this broadly applicable catalytic reaction. Overall, this reaction provides access to a great variety of carbonyl‐containing products through in situ transformation of the generated aroyl chloride. Combined experimental and computational studies support a reaction mechanism involving in situ generation of CO.

Insertions of olefins into metal-oxygen bonds are elementary steps of important catalytic processes, but well characterised complexes that undergo this reaction are rare, and little information on the effects of...