Direct Allylation of In Situ Generated Aldehyde Acyl Anions by Synergistic NHC and Palladium Catalysis

The direct regioselective allylation of in situ generated aldehyde acyl anions has been achieved by synergistic NHC and Pd catalysis. It provides an efficient access to valuable β,γ‐unsaturated ketones under mild reaction conditions starting from easily accessible allylic carbonates and aldehydes without any preactivation. The synergistic catalysis method demonstrated herein adds a new dimension to the area of metal‐mediated C allylation.     

Asymmetric Hydrogenation of In Situ Generated Isochromenylium Intermediates by Copper/Ruthenium Tandem Catalysis

The first asymmetric hydrogenation of in situ generated isochromenylium derivatives is enabled by tandem catalysis with a binary system consisting of Cu(OTf)₂ and a chiral cationic ruthenium–diamine complex. A range of chiral 1H ‐isochromenes were obtained in high yields with good to excellent enantioselectivity. These chiral 1H ‐isochromenes could be easily transformed into isochromanes, which represent an important structural motif in natural products and biologically active compounds. The chiral induction was rationalized by density functional theory calculations.