Superelectrophilic-Initiated C–H Functionalization at the β-Position of Thiophenes: A One-Pot Synthesis of trans-Stereospecific Saddle-Shaped Cyclic Compounds

Abstract

Superelectrophilic-initiated direct C–H functionalization of thiophenes at the β-position was developed. A series of trans-stereospecific [2,1-a]-IF-thiophene-fused cyclic compounds (4) with saddle-shaped structure were prepared in 17–30% yields through a one-pot superelectrophilic Friedel–Crafts reaction of dihydroindenofluorene with thiophene derivatives. From the crystal packing analyses of 4a, its skeleton shows both strong intermolecular π–π stacking and C–H···π stacking. Furthermore, the ring-dependent photophysical properties of 4 were confirmed by UV–vis absorption and photoluminescence spectroscopy as well as through the study of their fluorescence quantum yield.

Structural Study of Hydrogen-Bond Driven Cocrystallization of Pyridyl-Bithiophene Based Compounds

“…Column chromatography was carried out using silica gel (60 Å pore size, 230–400 mesh) from Silicycle. The synthetic procedures reported in the literature were used to synthesize T1 and T2 . , All the characterization spectra and crystallography tables are provided in the Supporting Information. 1 H and 13 C NMR spectra were recorded on a JEOL 400 MHz spectrometer in CDCl 3 or DMSO.…”

Dihydroindenofluorenes as building units in organic semiconductors for organic electronics

“…Finally, in 2019, [2,1- a ]-IF-derivatives decorated by thiophene cyclic compounds, [2,1- a ]-79-82 , were synthesized by superelectrophilic Friedel–Crafts reaction between [2,1- a ]-IF(OH) 2 and thiophene building units. 159 The photophysical properties of the four [2,1- a ]-79-82 were studied and compared to that of [2,1- a ]-IF(OH) 2 . The UV-vis absorption and emission spectra of [2,1- a ]-79-81 were almost similar with λ abs at ca.…”

Superelectrophiles: Recent Advances

“…In an effort to prepare thiophene-containing, shape-persistent macrocycles, a methodology was developed involving ionization of 11,12-dihydroindenop[2,1-a]fluoren-11,12-diol ( 29 ) and Friedel-Crafts reactions with thiophene derivatives ( Scheme 8 ) [ 32 ]. Thus, reaction of substrate 29 leads to product 30 in 20% yield from reaction with HBF 4 ·Et 2 O. Ionization of the substrate may go through the monocation intermediates or double ionization to give the superelectrophile 31 , an ion benefitting from an aromatic, 18π-electron system.…”