Boron‐Doped Polycyclic Aromatic Hydrocarbons: Synthesis and Functional Properties

The replacement of sp²‐hybridized carbon in polycyclic aromatic hydrocarbons (PAHs) by boron affords electron‐deficient π‐scaffolds due to the vacant p_z orbital of three‐coordinate boron. In this review article, research from the last decade is collected with a particular emphasis on the synthetic methodology towards boron‐containing PAHs bearing one or multiple boron centers (B_n‐PAHs). Different approaches based on transmetalation, oxidative cyclization (Scholl reaction), radical cyclization, Yamamoto coupling, and multistep cascade reactions will be discussed. The latter are shown to be particularly useful, as they circumvent the isolation of intermediates bearing reactive unshielded boron centers. The last part of this review will further illustrate the recent achievements in the synthesis and characterization of boratoarenes as well as N‐heterocyclic carbene‐ and cyclic (alkyl)(amino) carbene‐ stabilized boron‐doped PAHs (B‐PAHs) and conclude with an analysis and comparison of the redox properties realized by PAHs bearing single or multiple boron centers with regard to their envisioned application as n‐type organic semiconductors.