Palladium-catalyzed cross-couplings of functionalized 2-bromobenzofurans for atom-economic synthesis of 2-arylbenzofurans using triarylbismuth reagents

Triarylbismuthanes as Threefold Aryl‐Transfer Reagents in Regioselective Cross‐Coupling Reactions with Bromopyridines and Quinolines

“…Our studies have opened up a range of new reactivities with aryl bromides, iodides, and triflates under Pd‐catalysed conditions 13a–13d. Further investigations revealed that 2‐halothiophenes,13e 2‐bromofurans,13f and benzofurans13g also showed excellent coupling reactivity with triarylbismuth reagents. Continuing our investigations into triarylbismuth reagents, we were interested in exploring couplings with N ‐heterocyclic systems (Scheme ).…”

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

“…A trial reaction was performed with 2,3-dibromobenzofuran ( 1.1, 3.3 equiv) and tri( p -anisyl)bismuth (1 equiv) with Pd(OAc) 2 /PPh 3 , Cs 2 CO 3 (3 equiv) in N -methyl-2-pyrrolidone (NMP) at 90 °C for 1 h as protocol conditions [35]. This protocol furnished the preferential cross-coupling at the more electrophilic 2-Br position of 2,3-dibromobenzofuran ( 1.1 ) [29].…”

“…In this regard, the cross-coupling studies of triarylbismuth reagents in regioselective studies with functionalized bromobenzofurans were not reported so far (Scheme 1) [35]. Given the importance of threefold couplings’ reactivity realized with the sub-stoichiometric loading of triarylbismuths in the cross-coupling reactions [35–42], we report herein, a novel regio- and multi-coupling of bromobenzofurans with triarylbismuth reagents under palladium coupling conditions.…”

“…Given the importance of threefold couplings’ reactivity realized with the sub-stoichiometric loading of triarylbismuths in the cross-coupling reactions [35–42], we report herein, a novel regio- and multi-coupling of bromobenzofurans with triarylbismuth reagents under palladium coupling conditions.…”

Photoinduced synthesis of unsymmetrical diaryl selenides from triarylbismuthines and diaryl diselenides

“…On the other hand, triarylbismuthines are gaining interest as useful arylation reagents, because organobismuth compounds are nontoxic and have excellent reactivity, which has led to several applications in organic synthesis [33]. Therefore, numerous transition-metal-catalyzed coupling reactions with organobismuth compounds have been reported [34–53]. Although triphenylbismuthine can generate a phenyl radical [33,54] in the absence of a radical initiator simply by photoirradiation, few arylation reactions using this mechanism have been reported [55–56].…”