Reactions of C(6)F(5)Li with tetracyclone and 3-ferrocenyl-2,4, 5-triphenylcyclopentadienone: An (19)F NMR and X-ray crystallographic study of hindered pentafluorophenyl rotations

N-heterocyclic carbene-catalysed pentafluorophenylation of aldehydes

N-heterocyclic carbenes have been utilized as highly efficient organocatalysts to catalyse multifluorophenylation of aldehydes with fluorinated aryltrimethylsilanes to afford the corresponding adducts in 49–99% yields.

2000 Alcan Award Lecture Adventures in organometallic NMR: steric restraints, slowed rotations, and skeletal rearrangements

The structures and NMR fluxionality of a wide variety of organometallic complexes (including tetrahedral cluster cations and systems of the type (CnRn)ML3, where R = Et, Ph) are discussed. Barriers to tripodal and peripheral substituent rotations are reported, and the relevance of correlated rotations to molecular machines is outlined. Haptotropic shifts in (cyclopenta[def]phenanthrenyl)MLn and (cyclopenta[l]phenanthrenyl)MLn complexes are rationalized in terms of the aromatic character of the transition states. Likewise, the barriers to silatropic shifts in polyindenylsilanes can be correlated with the aromaticity of the intermediate isoindenes. Finally, the use of cobalt clusters to control cyclohexane ring conformations is described.Key words: NMR ring currents, fluxionality, correlated rotations, molecular rearrangements, haptotropic shifts.