Highly enantioselective nickel‐catalyzed alkene endo‐hydroarylations were accomplished with full selectivity by organometallic C−Hactivation. The asymmetric assembly of chiral six‐membered scaffolds proved viable in the absence of pyrophoric organoaluminum reagents within an unprecedented nickel/JoSPOphos manifold.
Asymmetric Synthesis of Isoindolones by Chiral Cyclopentadienyl-Rhodium(III)-Catalyzed CH Functionalizations
作者:Baihua Ye、Nicolai Cramer
DOI:10.1002/anie.201404895
日期:2014.7.21
Directed Cp*RhIII‐catalyzed carbon–hydrogen (CH) bond functionalizations have evolved as a powerful strategy for the construction of heterocycles. Despite their high value, the development of related asymmetric reactions is largely lagging behind due to a limited availability of robust and tunable chiral cyclopentadienyl ligands. Rhodium complexes comprising a chiral Cp ligand with an atropchiral
Nickel-Catalyzed Enantioselective Pyridone C–H Functionalizations Enabled by a Bulky <i>N-</i>Heterocyclic Carbene Ligand
作者:Johannes Diesel、Anastasiia M. Finogenova、Nicolai Cramer
DOI:10.1021/jacs.8b01181
日期:2018.4.4
Annulated pyridones are an important scaffold found in many biologically active compounds. A Ni(0)-catalyzed C-H functionalization of 2- and 4-pyridones is disclosed, providing access to annulated pyridones via enantioselective intramolecular olefin hydroarylation. Key to the success of the transformation was the development of a sterically hindered and tunable N-heterocyclic carbene ligand resembling a chiral version of IPr. This ligand allows for mild reaction temperatures, and leads to the annulated pyridones in excellent yields and enantioselectivities.