Synfacts 2019; 15(04): 0363
DOI: 10.1055/s-0037-1612324
Synthesis of Materials and Unnatural Products
© Georg Thieme Verlag Stuttgart · New York

A New Twist on Sydnones

Timothy M. Swager
Samuel I. Etkind
Yen-Pon E, Champagne PA, Plougastel L, Gabillet S, Thuéry P, Johnson M, Muller G, Pieters G, Taran F, Houk KN, Audisio D. * Université Paris-Saclary, Gif-sur-Yvette, France and University of California, Los Angeles, San José State University, USA
Sydnone-Based Approach to Heterohelicenes through 1,3-Dipolar-Cycloadditions.

J. Am. Chem. Soc. 2019;
141: 1435-1440
Further Information

Publication History

Publication Date:
19 March 2019 (online)



While helicenes have held the attention of chemists for years, expedient, selective syntheses to access such architectures are few and far between. In this report, Audisio and co-workers disclose a two-step method to a variety of pyrrazole-containing heterohelicenes through the cycloaddition of arynes and sydnones.



To form the helical product selectively, it was found that the phenanthryne cycloaddition partner was key. The use of naphthyne and benzyne cycloaddition partners resulted in eroded selectivity. Computational studies revealed that a C–H···π interaction stabilized the transition state for the helicene.