TY - JOUR
T1 - Heterohelicenes through 1,3-Dipolar Cycloaddition of Sydnones with Arynes
T2 - Synthesis, Origins of Selectivity, and Application to pH-Triggered Chiroptical Switch with CPL Sign Reversal
AU - Yen-Pon, Expédite
AU - Buttard, Floris
AU - Frédéric, Lucas
AU - Thuéry, Pierre
AU - Taran, Frédéric
AU - Pieters, Grégory
AU - Champagne, Pier Alexandre
AU - Audisio, Davide
N1 - Publisher Copyright:
© 2021 American Chemical Society. All rights reserved.
PY - 2021/6/28
Y1 - 2021/6/28
N2 - 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.
AB - 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.
KW - 1,3-dipolar cycloadditions
KW - DFT
KW - arynes
KW - circularly polarized luminescence
KW - mesoionics
UR - http://www.scopus.com/inward/record.url?scp=85114677518&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85114677518&partnerID=8YFLogxK
U2 - 10.1021/jacsau.1c00084
DO - 10.1021/jacsau.1c00084
M3 - Article
AN - SCOPUS:85114677518
SN - 2691-3704
VL - 1
SP - 807
EP - 818
JO - JACS Au
JF - JACS Au
IS - 6
ER -