Bottom-up Synthesis of Structurally Precise Graphene Nanoribbons
Chemistry and Chemical Biology
The Asao-Yamamoto benzannulation reaction transforms diaryl acetylenes into 2,3-diarylnaphthalenes with remarkable efficiency and tolerance of steric hindrance. This utility is most notable for molecular substrates containing multiple alkynes as well as poly(phenylene ethynylene)s. We will present further developments in this chemistry, including a variant that utilizes silyl-protected acetylenes to prepare a wide variety of congested aromatic systems that serve as precursors to carbon nanostructures and graphene nanoribbons. The regioselectivity of the reaction will also be discussed, which broadens the scope of the cycloaddition to access substituted polycyclic aromatic hydrocarbons with previously unavailable substitution patterns. Finally, the application of these methods to the preparation of graphene nanoribbons will be presented.