A new palladium catalyzed protocol for atom-efficient cross-coupling reactions of triarylbismuths with aryl halides and triflates

Palladium-catalyzed cross-couplings of allylic carbonates with triarylbismuths as multi-coupling atom-efficient organometallic nucleophiles

“…This intermediate upon transmetallation with triarylbismuth provides allylpalladium intermediates B and C which upon reductive elimination delivers arylated products D and E. The alkoxide as counter anion in A was proposed to activate arylbismuth species during transmetallation, as we have not used extra base to activate the Ar-Bi bond of triarylbismuths [28]. As the coupling sequence involves three aryl transfers from triarylbismuth, the in situ generated species such as Ar 2 BiOEt/ArBi(OEt) 2 are proposed to involve in the transmetallation steps of subsequent catalytic cycles.…”

“…reagents were reported under palladium-catalyzed conditions [11][12][13][14][15][16][17][18][19][20][21][22]. However, recently triarylbismuths have been demonstrated to be useful as multi-coupling organometallic nucleophiles for atom-efficient couplings with organic electrophiles [23][24][25][26][27][28][29][30][31][32][33][34][35][36]. In particular, the palladium-catalyzed cross-couplings of allyl bromide [37,38] with triarylbismuths were reported earlier.…”

Synthesis, structure and reactivity of complexes containing a transition metal–bismuth bond

“…Significant recent study has focussed on applications in catalysis, where bismuth species can act as cross-coupling agents in carbon-carbon [15][16][17][18][19][20][21][22][23][24][25][26], carbon-nitrogen [27] and carbon-oxygen [28] bond forming reactions. The low toxicity and ease of handling of arylbismuth compounds makes them comparable with organoboronic acids used in Suzuki-Miyaura type reactions, how- ever, the ability of triarylbismuth compounds to deliver three aryl groups per molecule allows atom-efficient reactions to be developed [29].…”

“…Miyaura and co-workers reported asymmetric palladium(II) catalysed 1,4-addition reactions of triphenylbismuth to cyclic and acyclic enones, also in aqueous media, with enantiomeric excesses of up to 95% [19]. Further studies include the use of triphenylbismuth in the cross-coupling of aryl bromides and iodides [17,18,20,21,23], acyl chlorides [22,28], vinyl iodides [24], allyl acetates [26] and ␣-arylacetyl chlorides [25]. Wang and co-workers recently demonstrated the compatibility of bismuth reagents with the use of a heterogeneous catalytic system [32].…”

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

“…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.…”