Regio‐ and Chemo‐selective C‐H Arylation of 3‐Bromothiophene: A Synthesis Shortcut to Versatile π‐Conjugated Building Blocks for Optoelectronic Materials.

Unlike traditional multi‐step synthetic approaches, we developed a single‐step synthesis of versatile π‐conjugated building blocks bearing post‐functionalizable C−H and C−Br bonds. Direct C−H arylation of 3‐bromothiophene with various iodo(hetero)aryls was successfully carried out with good regio‐ and chemo‐selectivity. Under optimized reaction conditions, 20 new compounds were facilely prepared in yields up to 91 %. One of the obtained compounds was demonstrated to further extend its conjugation length using a succinct synthetic plan to create two symmetrical oligo(hetero)aryls (<bold>MLC01</bold> and <bold>MLC02</bold>) that were fabricated as effective hole‐transporting materials (HTM) for perovskite solar cells (PSC). PSC devices utilizing <bold>MLC01</bold> as hole‐transport layer displayed promising power conversion efficiencies of up to 17.01 %. [ABSTRACT FROM AUTHOR]