Construction of a Highly Distorted Benzene Ring in a Double Helicene

• DOI: 10.1002/ange.201408390
• Publication Date: 2014-10-15T16:37:49Z
• Authors: Sigma Hashimoto; Soichiro Nakatsuka; Masaharu Nakamura; Takuji Hatakeyama
• Keywords: Helicene; Tandem

Abstract A P‐fused double helicene consisting of a highly distorted benzene ring, with bending angle 23°, has been synthesized by tandem intramolecular phospha‐Friedel–Crafts reaction. Despite the distortion and reduced aromaticity, shows thermal chemical stability. These are important features that make these compounds attractive for applications as new C 2 ‐symmetric bisphosphine ligand. The simple strategy proposed in this work can be used to prepare diverse range molecules.