Synthesis of Biphenyl- 4,4'-Diyl bis(phenyl-methanone) via Carbonylative Coupling

Abstract

Luminescent meterials have a major technological role for human kind in the form of application such as organic and inorganic light emitters for flat panel and flexible displays such as plasma displays, LCD displays and OLED displays. To develop a luminescent material with high colour purity, luminous efficiency and stability, we synthesized diketone by carbonylative Suzuki coupling in the presence of Pd(NHC) (NHC = N-heterocyclic carbene) complex as the catalyst. Carbonylative coupling of 4,42-diiodobiphenyl and phenylboronic acid was investigated to study in detail the catalytic ability of the Pd(NHC) complex. Reactions were carried out using both CO and metal carbonyls. Bis- (1,3-dihydro-1,3-dimethyl-2H-imidazol-2-ylidene) diiodo palladium was used as the catalytic complex. Reaction products biphenyl-4,4'-diyl bis(phenyl methanone) 3 and (4'-iodobiphenyl-4-yl)(phenyl)methanone 4 were obtained as a result of CO insertion into the palladium(II)-aryl bond. However, when pyridine-4-yl boronic acid was used in place of phenylboronic acid as the starting reagent, synthetic reaction yielding 3 and 4 were found not to occur.

“CO” as a Carbon Bridge to Build Complex C2-Branched Glycosides Using a Palladium-Catalyzed Carbonylative Suzuki–Miyaura Reaction from 2-Iodoglycals

“…The easy handling of solid Mo­(CO) 6 compared to hazardous gaseous carbon monoxide has motivated our choice to use this reagent as a “CO” generator . Despite its advantage, there have only been a few reports of carbonylative Suzuki–Miyaura reactions using Mo­(CO) 6 . Under these conditions, the desired compound 2a was isolated with a low yield of 26% (Table , entry 1).…”

“…In our case, we could imagine the same pathway via a molybdenum complex formed by a reaction between Mo­(CO) 6 and the boronic acid. Nevertheless, in the few examples of carbonylative Suzuki–Miyaura reactions using Mo­(CO) 6 in the literature, no mechanism investigations were presented . In our previously described aminocarbonylation process, we have shown that other sources of “CO” such as the system CHCl 3 /CsOH·H 2 O in toluene could be successfully used without a significant decrease in the product yield via a two-pot process, where the gaseous carbon monoxide was transferred by cannulation in the reaction flask .…”