Spirocyclic Aromatic Hydrocarbons (SAHs) and their Synthetic Methodologies

Spirocyclic aromatic hydrocarbons (SAHs) or spirocyclic arenes are functional building blocks in constructing amorphous organic/ polymeric semiconductors with high glass transition temperatures for organic electronic devices. In this review, SAHs were categorized into three classes - mono-spirocyclic aromatic hydrocarbons (MSAHs), heteroatom-containing spirocyclic aromatic hydrocarbons (HSAHs), and polyspirocyclic aromatic hydrocarbons (PSAHs) based on MSAHs and HSAHs. Various synthetic strategies of SAHs, viz., o-halobiaryl method, diarylfluorene method, dibiarylketone method, one-pot domino synthesis, tandem dilithiation method, alkyne-fused aromatization, allene method, and other related routes were summarized.