Primary Amines as Directing Groups in the Ru-Catalyzed Synthesis of Isoquinolines, Benzoisoquinolines, and Thienopyridines

Isoquinolines, benzoisoquinolines, thieno­[3,2-<i>c</i>]­pyridines and fused heteroaryl­[2,3-<i>c</i>] pyridines, with a wide variety of substituents at different positions of the aromatic or heteroaromatic rings, have been synthesized by Ru-catalyzed oxidative coupling of a broad range of benzylamines or heterocycles with internal alkynes. All benzylamines and heterocycles have unprotected primary amines as efficient directing groups

Influence of Temperature and Pressure on Cyclic Carbonate Synthesis Catalyzed by Bimetallic Aluminum Complexes and Application to Overall <i>syn</i>-Bis-hydroxylation of Alkenes

The effect of moderate temperatures (22–100 °C) and pressures (1–10 bar) on the synthesis of cyclic carbonates from epoxides and carbon dioxide catalyzed by a combination of bimetallic aluminum complexes and tetrabutylammonium bromide is investigated. The combined bimetallic complex and tetrabutylammonium bromide catalyst system is shown to be an order of magnitude more active than the use of tetrabutylammonium bromide alone at all temperatures and pressures studied. At the higher temperatures and pressures used, disubstituted epoxides become substrates for the reaction and it is shown that reactions proceed with retention of the epoxide stereochemistry. This allowed a route for the overall <i>syn-</i>bis-hydroxylation of alkenes to be developed without the use of hazardous metal based reagents. At higher pressures it is also possible to use compressed air as the carbon dioxide source

Cycloaurated Phosphinothioic Amide Complex as a Precursor of Gold(I) Nanoparticles: Efficient Catalysts for A³ Synthesis of Propargylamines under Solvent-Free Conditions

A C,S-cycloaurated complex based on an ortho-substituted phosphinothioic amide framework has been synthesized in high yield through tin­(IV)–Au­(III) transmetalation from the corresponding chlorodimethylstannyl derivative. The latter was prepared in a two-step process involving directed ortho lithiation/quenching with Me₃SnCl followed by Me/Cl exchange. The tin­(IV) and gold­(III) complexes have been characterized in solution and in the solid state. In both complexes, the phosphinothioic amide moiety acts as a C–C–P–S pincer ligand with formation of five-membered-ring metalacycles. The use of the gold­(III) complex in the amine–aldehyde–alkyne (A³) three-component coupling synthesis of propargylamines showed that the compound is transformed into the Sonogashira-type <i>o</i>-alkynylphosphinothioic amide with generation of Au­(I) nanoparticles with an average size of around 7 nm. These nanoparticles proved to be excellent catalysts in A³ coupling processes, providing propargylamines in high yields under solvent-free conditions with loadings as low as 0.1 mol % and without the use of additives