Enabling Bifunctionality and Hemilability of N-Heteroaryl NHC Complexes (pages 6606–6609)
Zephen G. Specht, Prof. Sara A. Cortes-Llamas, Hai N. Tran, Christoffel J. van Niekerk, Khing T. Rancudo, Prof. James A. Golen, Dr. Curtis E. Moore, Prof. Arnold L. Rheingold, Prof. Tammy J. Dwyer and Prof. Douglas B. Grotjahn
Version of Record online: 29 APR 2011 | DOI: 10.1002/chem.201100521
Functionalized carbene ligands: Increasing the steric bulk of R1 on 1 from H to tBu results in lengthening of the MN bond (by up to 9 %), lowered activation energy for chelate opening (cf. 2) by 17 kcal mol−1, and improved binding of an amine and intramolecular hydrogen bonding (3). Iridium species with R1=tBu are effective catalysts of base-free intramolecular hydroamination, unlike less-hindered analogues.