Miyaura Borylation and One‐Pot Two‐Step Homocoupling of Aryl Chlorides and Bromides under Solvent‐Free Conditions

Abstract

Solvent‐free protocols for Miyaura borylation and the one‐pot, two‐step homocoupling of aryl halides are reported for the first time. Bis(dibenzylideneacetone)palladium(0) [Pd(dba)2] is an optimal source of palladium for Miyaura borylation, while for one‐pot two‐step homocoupling palladium(II) acetate [Pd(OAc)2] gives highest yields. Aryl bromides are coupled most efficiently using the DPEphos ligand. Chlorides are coupled using XPhos. The developed protocols are robust, versatile and easily reproducible on a large scale.magnified image

High-quality conjugated polymers via one-pot Suzuki–Miyaura homopolymerization

“…To this end, a handful of research groups have investigated the scope of one-pot synthesis of biaryls in terms of catalyst, base and aryl halides. [17][18][19][20][21][22] Early discoveries have shown that bis(pinacolato) diboron could be used as a condensation reagent for the onepot synthesis of low to moderate molecular weight poly(arylene)s, 23 and that certain bases such as K 2 CO 3 may lead to oligomer formation in biaryl systems. 24 In 2009, Reynolds et al revisited this synthetic pathway and specically studied the effect of CsF on the homopolymerization of uorenes.…”

Palladium-catalyzed borylation of aryl (pseudo)halides and its applications in biaryl synthesis

“…PdCl 2 (PPh 3 ) 2 [25, 42] exhibited low activity for borylation of 4-chloroanisole (Table 1, entry 3). Catalytic systems Pd(PPh 3 ) 4 /PCy 3 [43], Pd 2 dba 3 /PCy 3 [43, 44], Pd 2 dba 3 /XPhos [28, 45], Pd 2 dba 3 /SPhos [28, 45], Pd(OAc) 2 /PCy 3 [43, 46], Pd(OAc) 2 /XPhos [45, 47] gave moderate to good yields (Table 1, entries 2 and 6–10). Then we tested room temperature for the reaction of 4-chloroanisole.…”

Synthesis of Biquinolines via a Pd‐Catalyzed Borylation Reaction

“…By taking this challenge, an initial synthetic scheme has been introduced upon the basis of several study (Scheme ) . The reaction involves Suzuki‐Miyaura borylation by using bispinacolatodiboron (B 2 Pin 2 ) wherein homo‐coupling products are obtained as side products along with major borylated products in the presence of sodium acetate as a base.…”

“…By taking this challenge, an initial synthetic scheme has been introduced upon the basis of several study (Scheme 1). [9][10][11][12][13][14][15] The reaction involves Suzuki-Miyaura borylation by using bispinacolatodiboron (B 2 Pin 2 ) wherein homo-coupling products are obtained as side products along with major borylated products in the presence of sodium acetate as a base. It is well known that Suzuki-Miyaura borylation reactions have higher functional group tolerance and that emerged as a positive point in this specific case when compared to oxidative cross coupling reactions requiring directing groups.…”