The first example of propylene production from 2-butene in promising yield is described by reacting trans-2-butene over tungsten hydrides precursor W-H/Al(2)O(3) at 150 °C and different pressures in a continuous flow reactor. The tungsten carbene-hydride active site operates as a "bi-functional catalyst" through the disfavoured 2-butene isomerisation on W-hydride and 2-butenes/1-butene cross-me...

Chan-Lam cross coupling allowed efficient synthesis of N,N'-disubstituted ortho-phenylene diamines bearing strong electron donating or withdrawing groups, such as nitro or methoxy groups, with moderate to high yields. These diamines can then be turned into N-heterocyclic carbene precursors after condensation with trimethyl orthoformate. The same strategy can also be utilized for the synthesis o...

A dual activation strategy integrating N-heterocyclic carbene (NHC) catalysis and a second Lewis base has been developed. NHC-bound homoenolate equivalents derived from α,β-unsaturated aldehydes combine with transient reactive o-quinone methides in an enantioselective formal [4 + 3] fashion to access 2-benzoxopinones. The overall approach provides a general blueprint for the integration of carb...

Metal carbenes have for a long time been classified as Fischer or Schrock carbenes depending on the oxidation state of the metal. Since the introduction of N-heterocyclic carbene complexes this classification needs to be extended because of the very different electronic character of these ligands. The electronic structure of these different kinds of carbene complexes is analysed and compared to...

A series of gold(I) complexes [AuCl(trz)] were synthesized that contain 1,2,3-triazolylidene (trz) ligands with variable wingtip groups. In the presence of AgBF4, these complexes undergo ligand redistribution to yield cationic complexes [Au(trz)2]BF4 in high yields as a result of efficient carbene transfer. Identical reactivity patterns were detected for carbene gold complexes comprised of Ardu...

A silicon carbide microtubular reactor has been used to measure branching ratios in the thermal decomposition of furan, C4H4O. The pyrolysis experiments are carried out by passing a dilute mixture of furan (approximately 0.01%) entrained in a stream of helium through the heated reactor. The SiC reactor (0.66 mm i.d., 2 mm o.d., 2.5 cm long) operates with continuous flow. Experiments were perfor...

The cover picture shows the crystal structure of an iridium complex with N-heterocyclic carbene-arsinidenide ligand. This represents carbene analogue rare transition metal-arsinidene complexes and has shortest iridium-arsenic bond length reported to date, indicating presence strong metal-arsenic π-interaction. More details are presented in communication A. Doddi et al. (DOI: 10.1002/zaac.202300...

Copper-alumanyl complexes, [LCu-Al(SiNDipp)], where L=carbene=NHCiPr (N,N?-diisopropyl-4,5-dimethyl-2-ylidene) and Me2CAAC (1-(2,6-diisopropylphenyl)-3,3,5,5-tetramethyl-pyrrolidin-2-ylidene) featuring unsupported Al?Cu bonds, have been prepared. Divergent reactivity observed with carbodiimides CO2 implies an ambiphilicity in the Cu–Al interaction that is dependent on identity of carbene co-lig...

Dialkyl heteroaroylphosphonates based on thiophene, pyrrole or furan have been prepared and their reactions with trimethyl phosphite investigated. Deoxygenation of the carbonyl groups in these heteroaroylphosphonates occurs to give carbene intermediates, which then undergo further reaction. In the case of the furan-3-oylphosphonates and those systems containing a thiophene or pyrrole ring, the ...

The first example of a biocatalytic strategy for the synthesis of thioethers via an intermolecular carbene S-H insertion reaction is reported. Engineered variants of sperm whale myoglobin were found to efficiently catalyze this C-S bond forming transformation across a diverse set of aryl and alkyl mercaptan substrates and α-diazoester carbene donors, providing high conversions (60-99%) and high...