Regioselective electrophilic aromatic borylation as a method for synthesising sterically hindered benzothiadiazole fluorophores

Abstract

A regioselective one-pot, three-step phenylation strategy has been applied to 4,7-diarylbenzo[c][1,2,5]thiadiazoles to restrict internal bond rotation and alter the molecules' fluorescence properties.

Derivatization of 2,1,3-Benzothiadiazole via Regioselective C–H Functionalization and Aryne Reactivity

“… 45 We obtained 11a from 10b via intramolecular Pd-catalyzed C4–H arylation 46 (Conditions K) with complete regioselectivity, which is accounted for by the greater ease with which C4–H activates under base-assisted palladation. 16 , 17 To the best of our knowledge, this marks the first example of direct C–H arylation as a route to fused BTD-based systems.…”

“…Fused carbazoles are key components of innumerable organic solar cells and other optoelectronic devices. , Tetracycles 11a and 11b (Scheme ) specifically represent a class of fused thiadiazolocarbazoles that have shown promise as electron transporters in electroluminescent materials . We obtained 11a from 10b via intramolecular Pd-catalyzed C4–H arylation (Conditions K) with complete regioselectivity, which is accounted for by the greater ease with which C4–H activates under base-assisted palladation. , To the best of our knowledge, this marks the first example of direct C–H arylation as a route to fused BTD-based systems.…”

“…The use of catalytic C–H functionalization as a tactic to extend the BTD π-system is in its infancy. To complement the range of reactions reported to date, 16 as well as to explore the prospects of addressing both C4–H and C6–H positions from a common directing group, we initially examined carboxylate-assisted 17 Ru-catalyzed arylations and Rh-catalyzed alkenylation using 4g as a substrate (Conditions M and N, respectively, Scheme 4 ). With one equivalent of bromoarene, the Ru system gave C4–H-arylated product 12a with very high regioselectivity (15:1 rr ), underscoring the greater preference of carboxylate-assisted C–H activation for the C4 position.…”

“…Recent years have seen C–H functionalization 14 emerge as a transformative technology for expediting synthesis through previously impossible reactions and increasingly sustainable protocols. 15 However, reports on the catalytic C–H functionalization of BTD have been sparse and overwhelmingly focused on Pd-catalyzed C4/C7 arylation, 16 where CMD-type processes most easily take effect. 17 …”

Immobilisation of benzo[c][1,2,5]thiadiazole (BTZ) within polymers of intrinsic microporosity (PIMs) for use in flow photochemistry

“…1A), which have recently gained attention as exible photocatalysts and uorophores. [7][8][9] Recent research has also highlighted the use of photoactive polymer materials as photosensitisers, including photosensitisers attached to Merrield resins, [10][11][12][13] cross-linked polymers, [14][15][16][17][18] conjugated porous polymers (CPPs), 19,20 and covalent organic frameworks (COFs). 21 The high surface area that such materials oen exhibit provides a high interfacial area for interaction with oxygen while also enhancing interaction with the solvent to aid in the materials dispersibility.…”