Some Observations on the Palladium-Catalyzed Triflate-Arene Cyclization of Electron-Rich Biaryl Substrates

Application of Palladium-Catalyzed C(sp2)–H Bond Arylation to the Synthesis of Polycyclic (Hetero)Aromatics

“…To overcome the previous limitations, i.e., all previously prepared derivatives using this method had a single functional group at positions 4, 5, 6, or 7, they applied the palladium-catalyzed triflate-arene cyclization reaction to the synthesis of polyoxygenated benzo[b]fluoranthene derivatives (Scheme 8). 30 It is worth noting that with highly methoxylated substrates, the addition of LiCl (thought to be necessary in most cases for palladium-catalyzed reactions involving triflates) had a deleterious effect on the reaction. In 1999, Dehaen and co-workers prepared rubicenes in excellent yields via a two-fold Pdcatalyzed C-H bond arylation with activation of C-Cl bonds using Pd(OAc)2 as catalyst with In 2018, Harper, Uribe-Romo and co-workers employed this Pd-catalyzed triflate-arene 5membered ring cyclization for the preparation of a wide range of dibenzo-and naphthofluoranthene polycyclic aromatic hydrocarbons (Scheme 10).…”

Synthesis of C3 Benzo[1,2‐e:3,4‐e′:5,6‐e′′]tribenzo[l]acephenanthrylenes (“Crushed Fullerene” Derivatives) by Intramolecular Palladium‐Catalyzed Arylation

“…The use of the more soluble Cs 2 CO 3 as the base increased the yield of 2 to 53 %. Tris(triflate) 15 could also be cyclized to give 2 , albeit in lower yield (11 %), by using [Pd(PPh 3 ) 2 Cl 2 ] (150 mol %) and excess NaOPiv in DMA at 120 °C 26…”

“…Arylation of this mixture with Pd(OAc) 2 , BnMe 3 NBr, and Cs 2 CO 3 in DMA at 130 °C for 24 h afforded 18 a , which was isolated in 26 % yield. Similarly, alkylation of 2,7,12‐triphenyltruxene ( 16 b )26 gave 17 b as a 5.5:1 anti / syn mixture in 71 % yield, which was treated with Pd(OAc) 2 , BnMe 3 NBr, and K 2 CO 3 in DMA at 160 °C to give 18 b in 38 % yield.…”

“…Truxene ( 1 ), tribenzyl derivatives 8 a and 8 b ,21 2,7,12‐tri‐ n ‐butyltruxene ( 16 a ),26 2,7,12‐triphenyltruxene ( 16 b ),26 and 1‐bromo‐2‐(bromomethyl)naphthalene26 were prepared according to known procedures. 1‐Methoxy‐2‐(bromomethyl)naphthalene was prepared by a small modification of a known method 26. The synthesis and X‐ray structure of syn ‐5,10,15‐tris(1‐methoxy‐2‐naphthylmethyl)‐10,15‐dihydro‐5 H ‐diindeno[3,2‐ a ;3′,2′‐ c ]fluorene 13 has been reported elsewhere 21…”

Palladium-Catalyzed IntramolecularArylation Reaction: Mechanism and Application for theSynthesis of Polyarenes

“…[21][22][23] With activated sub-strates, the palladium-catalyzed arylation has also been carried out intermolecularly. 24 The reaction has been proposed to proceed by oxidative addition of I to Pd(0) to form II, followed by a palladation step to give III.…”