Pt-Catalyzed Tandem Epoxide Fragmentation/Pentannulation of Propargylic Esters

摘要

The development of new pentannulation reactions continues to be an important pursuit in synthetic organic chemistry due to the prevalence of five-membered rings in natural products.While various traditional approaches such as the Nazarov,Pauson-Khand,and Karpf-Dreiding reactions have provided access to pentacyclic structures,there remains a need to develop more efficient organic transformations in this regard.Recently we reported a Pt-catalyzed pentannulation reaction,an example of which is outlined in eq 1.In these reactions,readily obtained propargylic esters such as 1 are converted to highly functionalized indenes (2)under platinum catalysis,presumably via the intermediacy of a metallocarbenoid.