Intermolecular Hetero-Diels–Alder Reactions of Photogenerated aza-<i>ortho</i>-Quinone Methides with Aldehydes
作者:Dong Liang、Li Rao、Cong Xiao、Jia-Rong Chen
DOI:10.1021/acs.orglett.9b03399
日期:2019.11.1
A visible-light-driven, perfluoroalkyl radical-mediated strategy for in situ formation of aza-o-QMs from readily available precursors is reported. Combination of this method with a Bronsted base thus enables an efficient and highly diastereoselective HDA reaction between such photogenerated aza-o-QMs and pi-electron-poor systems, aldehydes, providing high yielding and rapid access to valuable, diversely substituted dihydrobenzoxazines. DFT calculation elucidated the origins of stereochemistry of the products and disclosed the concerted property of the process.