- Yen-Pon, Expédite;
- Champagne, Pier Alexandre;
- Plougastel, Lucie;
- Gabillet, Sandra;
- Thuéry, Pierre;
- Johnson, Mizuki;
- Muller, Gilles;
- Pieters, Grégory;
- Taran, Frédéric;
- Houk, KN;
- Audisio, Davide
The first approach to pyrazole-containing helicenes via sydnone-aryne [3 + 2]-cycloaddition is described. An unprecedented regioselectivity in the cycloaddition step toward the more sterically constrained product was observed in the presence of extended aromatic scaffolds. DFT calculations enabled understanding the origin of this unexpected selectivity.