An N-heterocyclic carbene-catalyzed [3+3] cycloaddition reaction of acylthioureas with ynals is reported. Both N atoms in the thiourea substrate are activated as nucleophiles and incorporated inside ring system product. Pyrimidinthione derivatives bearing various substituents substitution patterns afforded products moderate to good yields.

The 1,3-diaryl-imidazolium chlorides IPr.HCl (aryl = 2,6-diisopropylphenyl), IMes.HCl (aryl = 2,4,6-trimethylphenyl) and IXy.HCl (aryl = 2,6-dimethylphenyl), precursors to widely used N-heterocyclic carbene (NHC) ligands and catalysts, were prepared in high yields (81%, 69% and 89%, respectively) by the reaction of 1,4-diaryl-1, 4-diazabutadienes, paraformaldehyde and chlorotrimethylsilane in d...

This work describes a complete laboratory experiment that involves the synthesis of ruthenium complex [Ru(p-cym)(NHC)Cl2] (NHC = N-heterocyclic carbene) and its use as catalyst for coupling hydrosilanes alcohols. The hydrogen gas produced in reaction is measured using an inverted buret to trap which allows student monitor evolution reaction. experience constitutes opportunity focus on experimen...

The polarographic reduction of aromatic carbodiimides in anhydrous aprotic solvents goes through a carbene intermediate by a diffusion controlled process in two one-electron steps. The first step is the rate-determining step and converts the carbodiirnide to a radical anion (6) that reduces further by a fast one-electron step to a carbene dianion intermediate (7). This abstracts an oxygen, ...

A triphenylphosphinegold(I)-catalyzed cyclopropanation of olefins using propargyl esters as gold(I)-carbene precursors is reported. This reaction provided the basis for the use of a DTBM-SEGPHOS gold(I) complex as a catalyst in the enantioselective (up to 94% ee) preparation of vinyl cyclopropanes with high cis-selectivity.

A library of 1,2,3-triazoles was synthesized from diverse alkynes and azides using catalytic amounts of silver chloride instead of copper compounds. In addition, a novel "abnormal" silver N-heterocyclic carbene complex was tested as catalyst in this process. The results suggest that the reaction requires only 0.5% of silver complex, affording 1,2,3-triazoles in good yields.

Dirhodium tetraacetate catalysed reaction of alpha-diazo-beta-keto-carboxylates and -phosphonates with arenecarboxamides gives 2-aryloxazole-4-carboxylates and 4-phosphonates by carbene N-H insertion and cyclodehydration; in stark contrast, dirhodium tetrakis(heptafluorobutyramide) catalysis results in a dramatic change of regioselectivity to give oxazole-5-carboxylates and 5-phosphonates.

Novel iron complexes bearing both cyclopentadienone and N-heterocyclic carbene ancillary ligands were obtained by a straightforward synthesis from Fe2(CO)9. The preparation represents a rare example of silver transmetallation involving iron. The reaction is general and occurs in the presence of variously functionalized NHC and cyclopentadienones.