The first Cu- and amine-free Sonogashira-type cross-coupling in the C-6-alkynylation of protected 2′-deoxyadenosine

Palladium nanoparticles supported on a titanium dioxide cellulose composite (PdNPs@TiO2–Cell) for ligand-free carbon–carbon cross coupling reactions

Well-dispersed non-spherical PdNPs with a diameter of 39–45 nm supported on a TiO₂–cellulose composite can be synthesized by a simple route, and used for many coupling reactions under mild reaction conditions.

Palladium complexes derived from N,N-bidentate NH-iminophosphorane ligands: synthesis and use as catalysts in the Sonogashira reaction

The addition of primary amines to the C=C bond of diphenylalkenyl iminophosphoranes yielded a new subtype of N,N-bidentate ligands bearing N=P(V)-C-C-NH backbones. These donor ligands reacted with PdCl(2)(COD) to give the corresponding σN,σN-palladium complexes containing secondary amino groups, bearing an intrinsically chiral nitrogen atom, and iminophosphorane units. These new complexes have been fully characterized by the use of spectroscopic techniques and X-ray crystallography. The comparison of the data extracted from their solution NMR spectra with their solid state structures demonstrated the conformational stability of their six-membered chelate ring and also the configurational stability of the chiral nitrogen atom, thus ruling out an arm-off racemization process. The addition of the chiral, racemic α-methylbenzylamine to the prochiral P-alkenyl iminophosphoranes yielded mixtures of the two expected diasteroisomeric ligands in low diastereoisomeric ratios. One of these mixtures was resolved into their components, each one in turn giving rise to a pair of diasteromeric palladium complexes epimeric at the amino nitrogen atom. One selected example of the new complexes efficiently catalyzes the copper- and amine-free Sonogashira reaction of aryl halides with acetylenes.

Arylsulfonylacetylenes as alkynylating reagents of Csp2-H bonds activated with lithium bases

Chameleon: a new strategy for the synthesis of a wide variety of alkynyl derivatives by the reaction of substituted arylsulfonylacetylenes with organolithium species is described. The high yields, the simplicity of the experimental procedure, the broad scope of this reaction, and the formation of C(sp)-C(sp2) bonds without using transition metals are the main features of this methodology.