Pd-Catalyzed Regioselective Mono-Arylation: Quinazolinone as the Inherent Directing Group for C(sp²)–H Activation

Abstract

The Pd-catalyzed quinazolinone-directed regioselective monoarylation of aromatic rings by C-H bond activation is developed. A broad substrate scope is demonstrated for both quinazolinone as well as diaryliodonium triflates. The use of a base was found to be crucial for this transformation, unlike for the known nitrogen-directed arylations. All of the novel quinazolinones of biological interest were synthesized by using the operationally simple Pd(II)-catalyzed arylation reaction.

Diaryliodoniums Salts as Coupling Partners for Transition-Metal Catalyzed C- and N-Arylation of Heteroarenes

“…The Pd(II)-catalyzed C4-selective arylation of isoquinolone using symmetrical diaryliodonium tetrafluoroborates was reported by Hong [79]. The reaction was conducted with Pd(OPiv) 2 (10 mol%) as a catalyst in DME at 120 • C for 24 h and the high regioselectivity was consistent with an electrophilic palladation pathway involving a Pd(II/IV) catalytic cycle (Scheme 14) [80]. A radical mechanism was ruled out since the addition of a scavenger in the reaction mixture did not affect the reaction.…”

C–H Activation and Alkyne Annulation via Automatic or Intrinsic Directing Groups: Towards High Step Economy

“…Mhaske et al . used quinazolinone as a DG in for Pd‐catalyzed C–H arylation to obtain novel quinazolinones of biological interest . These works revealed application prospect of DG in for rapid construction of natural product‐like and drug‐like molecules.…”

Rapid Construction of Fused Heteropolycyclic Aromatics via Palladium-Catalyzed Domino Arylations of Imidazopyridine Derivatives

“…Notably, when the reaction was conducted without base, the yield decreased to 32% in AcOH as the solvent (Table 1, entry 10), which suggested that AcOH played an important role in the reaction (Table 1, entry 1 versus entry 12). 14 We also examined the counteranion effect; the diaryliodonium salt with an anion of OTf gave the best yield of 83% (Table 1, entries 13−15). When we reduced the amounts of diphenyliodonium salt to 2.5 equiv, the isolated yield decreased to 67% (Table 1, entry 16).…”

“…K 2 HPO 4 was proven to be the best choice, affording 3aa in an excellent yield of 83%. Notably, when the reaction was conducted without base, the yield decreased to 32% in AcOH as the solvent (Table , entry 10), which suggested that AcOH played an important role in the reaction (Table , entry 1 versus entry 12) . We also examined the counteranion effect; the diaryliodonium salt with an anion of OTf gave the best yield of 83% (Table , entries 13–15).…”