Divergent Synthesis of Contorted Polycyclic Aromatics Containing Pentagons, Heptagon, and/or Azulene

Divergent synthesis of four contorted aromatics containing pentagons, a heptagon, and/or an azulene from the same difluorenyl pentacenediene precursor were realized in one step. The subtle differences in molecular structure were confirmed by X-ray crystallography. The mechanisms for the control of different products, which involve a ring-expansion rearrangement, Scholl reactions, and/or Mallory cyclization were proposed on the basis of control experiments and DFT calculations. Such development adds good structure versatility and materials accessibility to the study of contorted aromatics.

Automated summary

In this study, a one-step divergent synthesis of four contorted aromatics with pentagons, a heptagon, and/or an azulene from the same difluorenyl pentacenediene precursor was achieved. The subtle differences in molecular structure were confirmed by X-ray crystallography. The mechanisms underlying the control of different products, involving ring-expansion rearrangement, Scholl reactions, and/or Mallory cyclization, were proposed based on control experiments and DFT calculations. This development enhances the structural versatility and materials accessibility in the study of contorted aromatics.