Iridium-Mediated Asymmetric Hydrogenation of 2,3-Diphenylbutadiene: A Revealing Kinetic Study
摘要:
Hydrogenation of 2,3-diphenylbutadiene mediated by a chiral iridium carbene oxazoline complex was studied. The kinetics of the reaction showed that it occurred in two distinct stages. The first corresponded to slow consumption of the diene to form half-hydrogenated products, i.e., monoenes. After all the diene was consumed, however, the reaction was much faster and more stereoselective. These data were interpreted in terms of possible catalytic intermediates.
Iridium-Mediated Asymmetric Hydrogenation of 2,3-Diphenylbutadiene: A Revealing Kinetic Study
摘要:
Hydrogenation of 2,3-diphenylbutadiene mediated by a chiral iridium carbene oxazoline complex was studied. The kinetics of the reaction showed that it occurred in two distinct stages. The first corresponded to slow consumption of the diene to form half-hydrogenated products, i.e., monoenes. After all the diene was consumed, however, the reaction was much faster and more stereoselective. These data were interpreted in terms of possible catalytic intermediates.
Unwringing the ring: Methylenecyclopropanes reacted with vinyl and aryl Grignard reagents in the presence of a nickel catalyst to afford vinyl‐ and arylmagnesation products, respectively, through a selective CC bondcleavage (see scheme). The reaction provides a new method for the preparation of substituted homoallyl and allyl Grignard reagents.