A Modular Synthesis of Substituted Cycloparaphenylenes

• Published in: Chemistry : a European journal Vol. 28; no. 8; pp. e202104239 - n/a
• Main Authors: Kohrs, Daniel, Becker, Jonathan, Wegner, Hermann A.
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 07-02-2022; John Wiley and Sons Inc
• Subjects: [2+2+2] cycloaddition; carbon allotropes; Chemistry; cross-coupling; Cycloaddition; Cycloaddition Reaction; Electron transfer; macrocycles; solid-state structures; Substitutes; Synthesis; cross-coupling; carbon allotropes; macrocycles; solid-state structures; [2+2+2] cycloaddition
• ISSN: 0947-6539; 1521-3765; 1521-3765
• DOI: 10.1002/chem.202104239

Herein, we report a modular synthesis providing access to substituted cycloparaphenylenes (CPPs) of different sizes. A key synthon introducing two geminal ester units was efficiently prepared by [2+2+2] cycloaddition. This building block can be conveniently converted to macrocyclic precursors controlling the ring size of the final CPP. Efficient reductive aromatization through single‐electron transfer provided the substituted nanohoops in a straightforward manner. The tBu ester substitution pattern enables a tube‐like arrangement in the solid‐state governed by van der Waals interactions that exhibits one of the tightest packings of CPPs in tube direction, thus opening new avenues in the crystal design of CPPs.
A new synthesis provides access to different sized substituted cycloparaphenylenes (CPPs). The use of a key synthon in a sequence of macrocyclization by cross‐coupling with different reaction partners followed by aromatization allows a modular build‐up. The controlled introduction of substituents enables a tube‐like arrangement of these molecular carbon allotropes in the solid state.