Palladium-catalyzed approaches to indenes

Abstract

<p>In this thesis several palladium-catalyzed carboannulation methods have been developed for a variety of indene derivatives. Chapter 1 describes the synthesis of indenes by the palladium-catalyzed carboannulation of internal alkynes by functionalized aryl halides. The annulation proceeds under relatively mild reaction conditions and gives good yields of indenes. This annulation process also exhibits excellent regioselectivity and is particularly suited for the synthesis of hindered 2-substituted indenes. Chapter 2 deals with a palladium/copper-catalyzed coupling of terminal alkynes and aryl halides, followed by a copper-catalyzed intramolecular cyclization. This two-step annulation procedure has proven to be quite general for the synthesis of indenes from terminal alkynes bearing a variety of substituents. Chapter 3 presents a new method for the synthesis of indenes by the palladium-catalyzed arylation of arylalkynes bearing a carbon nucleophile. This procedure, which involves cyclization and arylation in a single step, provides a convenient means of synthesizing indenes in high yields. This reaction also tolerates considerable functionality, and is particularly suited for the synthesis of 3,4-diaryl substituted indenes from electron-deficient aryl halides.</p>