Abstract
AbstractWe present herein a synthetic endeavor to prepare the epoxy-lactone moiety commonly present in the C/D ring of highly oxygenated triterpenes. Two strategies are applied starting from ursolic acid: (i) Br+-promoted cyclization–isomerization for late-stage epoxidation, and (ii) one-step SeO2-promoted oxidative cyclization. Additionally, the desired epoxy-lactone moiety can be readily prepared on gram scale in one step by using the modified SeO2/TBHP/AcOH oxidative system.
Funder
National Natural Science of Foundation of China
Academician Expert Workstation of Yunnan Province
Ten Thousand Talents Program of Yunnan Province
Department of Education of Yunnan Province
Yunnan University of Chinese Medicine
Subject
Organic Chemistry,Catalysis