Chemo‐ and Enantioselective Insertion of Furyl Carbene into the N−H Bond of 2‐Pyridones
Kai Wang, Ziye Liu, Guangyang Xu, Ying Shao, Shengbiao Tang, Ping Chen, Xinhao Zhang, Jiangtao Sun
Abstract
Asymmetric carbene insertion reactions represent one of the most important protocols to construct carbon-heteroatom bonds. The use of donor-acceptor diazo compounds bearing an ester group is however a prerequisite for achieving high enantioselectivity. Herein, we report a chemo- and enantioselective formal N-H insertion of 2-pyridones that has been accomplished for the first time with enynones as the donor-donor carbene precursors. DFT calculations indicate an unprecedented enantioselective 1,4-proton transfer from O to C. The rhodium catalyst provides a chiral pocket in which the steric repulsion and the π-π interaction of the propeller ligand play a critical role in determining the selectivities.