"Heterohelicenes through 1,3-Dipolar Cycloaddition of Sydnones with Ary" by Expédite Yen-Pon, Floris Buttard et al.
 

Heterohelicenes through 1,3-Dipolar Cycloaddition of Sydnones with Arynes: Synthesis, Origins of Selectivity, and Application to pH-Triggered Chiroptical Switch with CPL Sign Reversal

Document Type

Article

Publication Date

6-28-2021

Abstract

Regioselective access to heterohelicenes through the 1,3-dipolar cycloaddition of sydnones with arynes is described. Novel access to sydnones and poly(hetero)aromatic aryne precursors allowed the introduction of chemical diversity over multiple positions of the helical scaffolds. The origins of the unconventional regioselectivity during the cycloaddition steps was systematically investigated using density functional theory (DFT) calculations, unveiling the key features that control this reactivity, namely, face-to-face (π···π) or edge-to-face (C-H···π) interactions, primary orbital interactions and distortion from coplanarity in the transition structures (TSs) of the transformation. From the library of 24 derivatives synthesized, a pyridyl containing derivative displayed reversible, red-shifted, pH-triggered chiroptical switching properties, with CPL-sign reversal. It is found that protonation of the helicene causes a change of the angle between the electric and magnetic dipole moments related to the S1→ S0transition, resulting in this rare case of reversible CPL sign inversion upon application of an external stimulus.

Identifier

85114677518 (Scopus)

Publication Title

Jacs Au

External Full Text Location

https://doi.org/10.1021/jacsau.1c00084

e-ISSN

26913704

First Page

807

Last Page

818

Issue

6

Volume

1

Grant

ANR-17-CE07-0035

Fund Ref

Agence Nationale de la Recherche

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