Transition‐Metal‐Catalyzed Alkyne Hydroarylation with Arylmetals and Aryl Halides

The aryl alkene is one of the most ubiquitous molecular scaffolds found in diverse natural products, materials, and pharmaceuticals. Aryl alkenes are also essential synthetic intermediates in both industrial and academic laboratories. Nevertheless, traditional preparative methods have fundamental disadvantages, such as the necessity of lengthy synthetic operations and difficulty in the site‐ and stereoselective construction of multiply substituted derivatives. The development of a more straightforward and site‐ and stereoselective method to prepare aryl alkenes has therefore been an important objective in organic chemistry. A particularly attractive method to synthesize aryl alkenes is transition‐metal‐catalyzed alkyne hydroarylation using aryl donor reagents, which proceeds through the formal addition of Ar–H across the carbon–carbon triple bond of an alkyne. This chapter provides an overview of alkyne hydroarylations catalyzed by homogeneous metal catalysts. The mechanism, selectivity, scope and limitations, and experimental conditions of transition‐metal‐catalyzed alkyne hydroarylations are surveyed according to the aryl donor reagent and its role in the reaction; namely, (1) alkyne hydroarylations using arylmetal reagents (alkyne carbometallation/protonation), and (2) alkyne hydroarylations using aryl halides (reductive Heck reaction).