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Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
Published on: August 22, 2018
Intramolecular Azo Coupling Reaction of Binaphthyl Compounds: Synthesis of Pyrazole-Containing Helicene-Like
Yasushi Yoshida1, Naoyuki Aso1, Takashi Karatsu1
1Molecular Chirality Research Center, Graduate School of Engineering, Chiba University, 1-33, Yayoi-cho, Inage-ku, Chiba-shi, Chiba 263-8522, Japan.
Abstract:
A method for accessing pyrazole-containing helicene-like molecules from easily accessible NOBIN derivatives was developed. The reaction proceeded efficiently via diazonium salt intermediates, which provided a series of helicene-like molecular products in yields of 77%-89% regardless of their steric and electronic natures. The photophysical properties of the products were investigated. The 3,3'-disubstituted molecules showed a characteristic blue shift in their emission spectra. Product derivatizations were conducted, and interesting reactivities toward nucleophiles were observed.
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