Synthesis of nitrogen-containing polycyclic aromatic molecules by strain-enhanced 1,3-dipolar cycloaddition

Abstract

Nitrogen-containing polycyclic aromatic molecules (NPAMs) have attracted much attention in recent decades for their intriguing structures and properties, as well as potential to work as building blocks for the bottom-up synthesis of nitrogen-containing graphene, carbon nanotubes and fullerenes. The 1,3-dipolar cycloaddition reaction between compounds with unsaturated C-C bonds and π-extended azomethine ylide has proved to be an effective method for synthesizing NPAMs with large π-surface. However, substrate scope and yield of the reaction are limited by the low reactivity of certain unsaturated C-C bonds. In this thesis, we introduce molecular strain in these inactive substrates to promote a strain-enhanced 1,3-dipolar cycloaddition. These reactions give novel NPAMs such as azacorannulenophane and azahexabenzocoronenium with short synthetic route and improved yield. The resulting NPAMs also exhibit unique structural and physical characteristics, which provides more insights into the synthesis and properties of π-extended NPAMs.