Synthesis of a new fluorophore: wavelength-tunable bisbenzo[f]isoindolylidenes

Abstract

A novel fluorophore has been synthesized using readily available dipropargyl benzenesulfonamides. These fluorophores possess several advantages, such as exceptional photostability, high fluorescence quantum yield, and tunable emission wavelengths.

Regio- and Diastereoselective Radical Dimerization Reactions for the Construction of Benzo[f]isoindole Dimers

“…Instead, an overoxidized compound 13 was formed. Based on our previous findings, 43 it is likely that 13s initially undergoes cyclization in the presence of a base, followed by immediate oxidation to form the delocalized radical intermediate 13′. The steric effect of the 2,6-dimethyl group causes the aryl group of R 2 to be nearly perpendicular to the core benzo[f ]isoindole structure (dihedral angle = 86°).…”

“…Based on these studies of the mechanism and previous work, a possible reaction pathway was proposed and is shown in Figure c. The substrate A undergoes an initial rearrangement to form the diallenyl benzenesulfonamide intermediate B , which then cyclizes to generate the annulated intermediate C .…”

“…Moreover, since the spin densities of C1 and C3 are comparable, the dimerization reaction proceeds preferentially at the position with lower site resistance. Based on these studies of the mechanism and previous work, 43 Specifically, when R 1 is a primary alkyl group with less steric hindrance, the radicals dimerize on the carbon attached with the alkyl chain. Divergently, when R 1 is a bulkier cyclohexyl group, the radical dimerizes on the carbon near the aryl group (R 2 ).…”

“…Extensive studies have been undertaken in the last few decades regarding the formation of intricate carbon–carbon bonds through the cyclization reaction of CC bonds. − By controlling the cyclization step, it is possible to combine multiple alkynyl groups and form cyclic or polycyclic structures, thereby simultaneously constructing multiple carbon–carbon bonds in a single reaction. , This strategy not only demonstrates the diversity and potential of alkynes but also plays a crucial role in synthesizing complex organic molecules with biological activity and specific functionality. − Herein, we present a novel method for the formation of benzo­[ f ]­isoindole dimers through cascade cyclization, isomerization, and an oxidative radical dimerization reaction. The reaction was carried out with dipropargylbenzenesulfonamides as the substrates in the presence of a base and an oxidant (Figure b).…”