Palladium‐Catalyzed Chemoselective Borylation of (Poly)halogenated Aryl Triflates and Their Application in Consecutive Reactions

Abstract

This study reports the palladium-catalyzed chemoselective borylation of (poly)halogenated aryl triflates with a reactivity order of CÀ Cl > CÀ OTf. A catalyst system comprising Pd(OAc) 2 and SelectPhos (L1) enables a reaction with high reactivity and chemoselectivity. The consecutively chemoselective borylation reaction followed by the chemoselective intermolecular Suzuki-Miyaura reaction can be performed using a one-pot two-step approach to synthesize unsymmetrical biaryl compounds containing the triflate moiety. The reaction can be scaled up to the gram scale without diminishing the yield and chemoselectivity.

Recent advances in the application of ligands in palladium-catalyzed chemoselective coupling reactions at C–Br, C–OTf, and C–Cl sites

“…Subsequently, the Pd/ L45 catalytic system can be applied to perform chemoselective borylation and Suzuki–Miyaura coupling of chloroaryl triflates in a one-pot, two-step manner without the addition of a palladium source or ligand after the first step. 133 This approach allows for smooth coupling to yield O -triflylaryl products and demonstrates the versatility and effectiveness of L45 .…”

“…133 The system successfully achieved a chemoselective borylation reaction of chloroaryl triflates, producing only chloride-reacted products, without any diborylated products (Scheme 21). 133…”

“…By optimizing the reaction conditions, the method can be applied to heteroaryl- and electron-deficient substrates, with good to excellent yields of up to 95% (Scheme 21). 133…”

“…Later, the chemoselective borylation of haloaryl triflates was demonstrated using L45 as a ligand. 133 The system successfully achieved a chemoselective borylation reaction of chloroaryl triflates, producing only chloride-reacted products, without any diborylated products (Scheme 21). In addition, the catalytic system effectively suppresses selfcoupling products.…”

“…By optimizing the reaction conditions, the method can be applied to heteroaryl-and electron-deficient substrates, with good to excellent yields of up to 95% (Scheme 21). 133 Moreover, intramolecular competition reactions of bromochloroaryl triflates were demonstrated, resulting in reactions only at the bromide site. Subsequently, the Pd/L45 catalytic system can be applied to perform chemoselective borylation and Suzuki-Miyaura coupling of chloroaryl triflates in a one-pot, two-step manner without the addition of a palladium source or ligand after the first step.…”