Both square planar and tetrahedral isomers of the four-coordinate complex [Co(Bc(tBu))2] with a bis(3-tert-butylimidazol-2-ylidene)borate ligand (Bc(tBu)) have been isolated while only a tetrahedral configuration was found for the Fe(ii) analogue [Fe(Bc(tBu))2]. Novel co-crystals containing both isomers of [Co(Bc(tBu))2] have been obtained from recrystallization.

A catalytic method has been developed for construction of indoline-2-thiones containing an all-carbon quaternary centre at the C-3 position. Successive treatment of α,β-unsaturated aldehydes bearing an isothiocyanato moiety with an in situ generated N-heterocyclic carbene and an appropriate heteroatomic nucleophile provided the 3,3-disubstituted indoline derivatives in moderate to good yields.

Highly functionalized dihydropyridinones were synthesized via the N-heterocyclic carbene-catalyzed enantioselective [4 + 2] annulation of α-chloroaldehydes and azadienes. Hydrogenation of the resulted dihydropyridinones afforded the corresponding piperidinones with high enantiopurity.

An unique long-range 1,7-bromination reaction is observed in gold(III) complexes of N-(aryl)imino functionalized N-heterocyclic carbene with the bromination occurring at two different carbon (sp2 and sp3) centers spatially separated by ca. 6.4 A but existing in extended conjugation to each other. In particular, the unusual distant 1,7-brominated gold(III) complexes [1-R-3-{N-(p-bromo-2,6-di-i-p...

The N-heterocyclic carbene-catalyzed [3 + 3] cyclocondensation of bromoenals and hydrazones is developed to give the corresponding chiral 4,5-dihydropyridazones in good yields with excellent enantioselectivities.

Medium-sized ynolides were prepared by the Lewis acid-mediated fragmentation of bicyclic γ-silyloxy-β-hydroxy-α-diazolactones in which the Cβ-Cγ bond is the ring fusion bond. Although these lactone fragmentation substrates reacted somewhat less efficiently than their carbocyclic counterparts, the fragmentation provided 11-membered ynolides in up to 84% yield. Unlike prior fragmentations of simi...

Electrogenerated N-heterocyclic carbene can behave as an organocatalyst in the Staudinger reaction (from imine and acyl chloride) in a very polar solvent, such as an ionic liquid.

Two novel pyridine pendant-armed macrocycles structurally reinforced by an ethyl bridge, either between adjacent nitrogens (for side-bridged) or non-adjacent nitrogens (for cross-bridged), have been synthesized and complexed with a range of transition metal ions (Co2+, Ni2+, Cu2+ and Zn2+). X-ray crystal structures of selected cross-bridged complexes were obtained which showed the characteristi...