Angewandte Chemie International Edition
© WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
Cover Picture: Heterolytic Dihydrogen Activation by a Frustrated Carbene–Borane Lewis Pair / Hydrogen and Amine Activation by a Frustrated Lewis Pair of a Bulky N-Heterocyclic Carbene and B(C6F5)3 (Angew. Chem. Int. Ed. 39/2008)
Forcing a square peg into a round hole: tBu2ImC: and B(C6F5)3 form a frustrated Lewis pair (FLP), allowing the synergistic activation of H2. On page 7428 ff., M. Tamm et al. describe how the irreversible formation of an abnormal carbene–borane adduct eliminates mismatching between acid and base so that this system can circumvent frustration at the expense of activity. In addition, D. W. Stephan and P. A. Chase demonstrate on page 7433 ff. that this FLP combination not only effects heterolytic cleavage of H2, but also of amine N-H bonds.
Also of Interest
Bifunctional Cyclopropane Derivatives
In their Communication on page 7424 ff., H. Ito, M. Sawamura et al. describe the regio- and enantioselective copper-catalyzed synthesis of boron–silicon bifunctional cyclopropane derivatives from silylated allylic carbonates and a diboron species.
The Review by R. J. M. Klein Gebbink and B. M. J. M. Suijkerbuijk on page 7396 ff. gives an overview of the diverse nature of metalated porphyrins. The spectrum ranges from reactive intermediates to dyads and triads for photochemical change separation.
A. Baceiredo, G. Bertrand et al. describe in their Communication on page 7530 ff. the isolation of a cyclic five-membered vinylidenephosphorane that is stable at room temperature. This strongly electron-donating ligand gives rise to very robust transition-metal complexes.