Selenium-π-Acid Catalyzed Oxidative Functionalization of Alkynes: Facile Access to Ynones and Multisubstituted Oxazoles

Article abstract of DOI:10.1021/acscatal.8b01595

Unprecedented selenium-catalyzed propargylic oxidation of alkynes is disclosed. Various propargylphosphonates and 3-alkynoates were efficiently converted to valuable ynones via unusual C-C triple bond migration and deselenenylation at a vinyl carbon. By the strategies of tautomerization of enamine intermediate and S_N2 displacement, similar conditions were effective for the oxidative difunctionalization of ynamides to afford multisubstituted oxazoles with high regioselectivity. Mechanistic studies revealed these detailed processes.