87148-60-5Relevant academic research and scientific papers
Palladium-catalyzed Sonogashira coupling reactions in γ-valerolactone-based ionic liquids
Orha, László,Tukacs, József M.,Kollár, László,Mika, László T.
supporting information, p. 2907 - 2913 (2019/12/14)
It was demonstrated that the γ-valerolactone-based ionic liquid, tetrabutylphosphonium 4-ethoxyvalerate as a partially bio-based solvent can be utilized as alternative reaction medium for copper- and auxiliary base-free Pd-catalyzed Sonogashira coupling reactions of aryl iodides and functionalized acetylenes under mild conditions. Twenty-two cross-coupling products were isolated with good to excellent yields (72–99%) and purity (>98%). These results represent an example which proves that biomass-derived safer solvents can be utilized efficiently in common, industrially important transformations exhibiting higher chemical and environmental efficiency.
Ppm Pd-catalyzed, Cu-free Sonogashira couplings in water using commercially available catalyst precursors
Jin, Bo,Gallou, Fabrice,Reilly, John,Lipshutz, Bruce H.
, p. 3481 - 3485 (2019/03/28)
A new catalyst that derives from commercially available precursors for copper-free, Pd-catalyzed Sonogashira reactions at the sustainable ppm level of precious metal palladium under mild aqueous micellar conditions has been developed. Both the palladium pre-catalyst and ligand are commercially available, bench stable, and highly cost-effective. The catalyst is applicable to both aryl- and heteroaryl-bromides as educts. A wide range of functional groups are tolerated and the aqueous reaction medium can be recycled. An application to a key intermediate associated with an active pharmaceutical ingredient (ponatinib) is discussed.
Use of ruthenium/alumina as a convenient catalyst for copper-free Sonogashira coupling reactions
Park, Soyoung,Kim, Min,Dong, Hyun Koo,Chang, Sukbok
, p. 1638 - 1640 (2007/10/03)
It has been found that a new and practical catalyst system of ruthenium-supported on alumina carries out copper-free Sonogashira coupling reactions with high efficiency over a wide range of substrates under mild and convenient conditions.
A Synthesis of Conjugatively Bridged Bis- and Tris-5-(2,2′-Bipyridines): Multitopic Metal Ion-Binding Modules for Supramolecular Nanoengineering
Baxter
, p. 1257 - 1272 (2007/10/03)
An efficient preparation of linear and curved bis- and branched tris-5-(2,2′-bipyridines) of nanoscopic dimensions possessing rigid conjugated bridges is presented. The synthesis, which avoids the need of protection/deprotection methodology, utilizes central bridge precursors which are outwardly diand trifunctionalized with a 5-(2-chloropyridine) synthon via a chemoselective palladium-catalyzed Sonogashira or Negishi cross-coupling protocol to yield the bridged linear (5a-c, 5f,g) and curved (6, 7) bis- and branched (8) tris-5-(2-chloropyridines). Under more forcing conditions, the ethynebridged 5-(2-chloropyridines) undergo the Stille cross-coupling reacton with 2-trimethylstannylpyridines to afford the conjugatively bridged linear (1a,b, 1g-j) and curved (2a,b, 3a,b) bis- and branched, (4a,b) tris-5-(2,2′-bipyridines) in good overall yields. The phenyl- and biphenyl-bridged linear bis-5-(2,2′-bipyridines) (1c-f) were best prepared from the bis-5-(2-bromopyridines) (5d,e) to ensure completion of the Stille cross-coupling reactions. The Stille cross-couplings showed a marked substituent effect in which the terminally phenylated bis- and tris-5-(2,2′-bipyridines) were formed in higher yields than the methyl-substituted analogues with the same bridge. The advantages of the methodology lie in its synthetic convenience and adaptibility for creating multitopic metal ion-binding scaffolds with a potentially very large variety of bridging units and substituents on the terminal pyridine rings. The bridged 5-(2-chloropyridines) may also serve as precursors for the fabrication of metal ion-coordinated conjugated polymers.
