Stereoconvergent Direct Ring Expansion of Cyclopropyl Ketones to Cyclopentanones
作者:Jiru Shao、Yue Fu、Sunewang R. Wang
DOI:10.1021/acs.orglett.3c00025
日期:2023.1.27
Recyclization of the ring-opening species of alkyl cyclopropyl ketones to cyclopentanones, which proceeds through an unfavored 5-endo-trig cyclization predicted by Baldwin’s rules, is elusive. Herein, as assisted by a strong aryl donor and the Thorpe–Ingold strain on a quaternary cyclopropyl center, stereoconvergent direct ringexpansion of cyclopropyl ketones to cyclopentanones promoted by TfOH or BF3·Et2O is