A Highly Warped Heptagon-Containing sp2 Carbon Scaffold via Vinylnaphthyl π-Extension

Jeffrey M Farrell; Vincenzo Grande; David Schmidt; Frank Würthner

doi:10.1002/anie.201909975

A Highly Warped Heptagon-Containing sp² Carbon Scaffold via Vinylnaphthyl π-Extension

Angew Chem Int Ed Engl. 2019 Nov 11;58(46):16504-16507. doi: 10.1002/anie.201909975. Epub 2019 Sep 30.

Authors

Jeffrey M Farrell¹, Vincenzo Grande², David Schmidt², Frank Würthner^{1

2}

Affiliations

¹ Institut für Organische Chemie, Universität Würzburg, Am Hubland, 97074, Würzburg, Germany.
² Center for Nanosystems Chemistry (CNC), Universität Würzburg, Theodor-Boveri-Weg, 97074, Würzburg, Germany.

Abstract

A new strategy is demonstrated for the synthesis of warped, negatively curved, all-sp² -carbon π-scaffolds. Multifold C-C coupling reactions are used to transform a polyaromatic borinic acid into a saddle-shaped polyaromatic hydrocarbon (2) bearing two heptagonal rings. Notably, this Schwarzite substructure is synthesized in only two steps from an unfunctionalized alkene. A highly warped structure of 2 was revealed by X-ray crystallographic studies and pronounced flexibility of this π-scaffold was ascertained by experimental and computational studies. Compound 2 exhibits excellent solubility, visible range absorption and fluorescence, and readily undergoes two reversible one-electron oxidations at mild potentials.

Keywords: C−C coupling; arenes; carbon; curvature; polycyclic aromatic hydrocarbons.