Selective C-C Bond Scission of Ketones via Visible-Light-Mediated Cerium Catalysis
作者:Yilin Chen、Jianbo Du、Zhiwei Zuo
DOI:10.1016/j.chempr.2019.11.009
日期:2020.1
catalytic manifold for the selectiveC–Cbond scission of ketones via the exploitation of the ligand-to-metal charge transfer (LMCT) excitation mode. Through a cooperative utilization of Lewis acid catalysis and LMCT catalysis, the C–Cbond of ketones could be selectively and effectively cleaved, enabling the installation of different functionalities at each carbon of the cleaved C–Cbond through a sequential
Bu(3)SnH-mediated aryl radicalcyclizationonto methylenecycloalkanes having a phenylthio, an ester, or a nitrile group at the terminus of the alkenic bond provides exclusively exo cyclization products. The results are in sharp contrast to those reported for nonsubstituted methylenecycloalkanes, which give exclusively endo cyclization products. Formation of endo cyclization products has been suggested
We herein report the development of a sterically hindered and electron-rich P-chiral monophosphorus biaryl ligand that has enabled a general and efficient enantioselective intramolecular alpha-arylation, providing access to a wide series of [4.4], [4.5], and [4.6]-spirocycles with chiral benzylic quaternary carbons in high yields with good to excellent enantioselectivities. A pronounced water effect on enantioselectivity is observed.