The Versatility of the Aryne–Imine–Aryne Coupling for the ­Synthesis of Acridinium Photocatalysts

Abstract

The increasing use of acridinium photocatalysts as sustainable alternative to precious metal-based counterparts encourages the design and efficient synthesis of distinct catalyst structures. Herein, we report our exploration of the scope of the aryne–imine–aryne coupling reaction combined with a subsequent acridane oxidation for a short two-step approach towards various acridinium salts. The photophysical properties of the novel photocatalysts were investigated and the practical value was demonstrated by a cation-radical accelerated nucleophilic aromatic substitution reaction.

Isoacridone dyes with parallel reactivity from both singlet and triplet excited states for biphotonic catalysis and upconversion

“…1b, see ESI † for more details). [80][81][82] Targeting high intersystem crossing quantum yields (ISC-QYs), we introduced iodine atoms at different positions of the aryl-substituent at C-9 of the acridinium core, resulting in four different isoacridone dyes (shown in Fig. 1b) that were explored in comparative fashion (PS(I)-PS(IV)).…”

Synthesis of Helical and Planar Extended‐Phenanthridinium Salts

“…[4][5][6] In recent studies, we investigated a short two-step route towards diverse acridinium salts involving the aryne-imine-aryne coupling reaction [7] followed by the subsequent oxidation of the acridane intermediate (Scheme 1,a). [8,9] Herein, we now disclose the utilization of this methodology for larger polycyclic aryne substrates. The unique reactivity of arynes containing an extended π-system under typical aryne-imine-aryne coupling conditions thereby lead to the notable formation of the tetrabenzo[a,c,i,k]phenanthridin-17ium system (Scheme 1,b).…”