Expedient Synthesis of Phenanthrenes via In(III)-Catalyzed 6-<i>Exo</i>-<i>Dig</i> Cycloisomerization

Abstract

This paper documents the first example of In(III)-catalyzed selective 6-exo-dig hydroarylation of o-propargylbiaryls and their subsequent double-bond migration to obtain functionalized phenanthrenes. Electron-rich biaryl substrates undergo hydroarylation more effectively, and the substrates with various types of substituents on the alkyne can also be smoothly and selectively converted to phenanthrenes.