Assembly of [5]Helicene Subunits by Palladium-Catalyzed Reactions: Synthesis, Structures, Properties, and Theoretical Study of Multiple Helicenes

Abstract

Helicenes, a class of non-planar polyaromatic hydrocarbons whose characteristic is helicity, are fascinating functional molecules with unique optical and electronic properties. In recent years, “multiple helicenes” having plural helicities in a single molecule have developed rapidly into an attractive research field due to their highly distorted structure, with the partially delocalized π-systems reflecting the assembly of plural helicities. In this account, we describe our recent work covering the synthesis, structures, properties, and theoretical study of multiple helicenes, DH-1, HH-2, and TH-3. Our strategy for the synthesis of multiple helicenes includes the assembly of [5]helicene subunits by palladium-catalyzed reactions.