Pd-Catalyzed Copper-Free Carbonylative Sonogashira Reaction of Aryl Iodides with Alkynes for the Synthesis of Alkynyl Ketones and Flavones by Using Water as a Solvent

Abstract

The Pd-catalyzed copper-free carbonylative Sonogashira coupling reaction to synthesize alkynyl ketones from terminal alkynes and aryl iodides was achieved by using water as a solvent. The reaction was carried out at room temperature under balloon pressure of CO with Et(3)N as a base. The developed method was successfully applied to the synthesis of flavones.

Quick Assembly of 1,4-Diphenyltriazoles as Probes Targeting β-Amyloid Aggregates in Alzheimer's Disease

“…The use of "click chemistry", modified Huisgen condition, 23 to quickly assemble various interesting molecules has attracted a lot of interest as an approach for drug development. [24][25][26][27][28][29][30] Click chemistry reactions, which commonly employ a Cu(I)-catalyzed azide-alkyne cycloaddition (CuAAC), have several distinctive advantages, including use of modular and fragmentbased reagents, wide scope, stereospecificity, easy separation, and high yield. [31][32][33] Resveratrol, 6, is a natural antioxidant normally present in red wine, which may modify the metabolism of lipoproteins and may have beneficial effects of antioxidants.…”

Catalyzed Reactions of Alkynes in Water

“…Later, Yang and co-workers reported a copper free version of the carbonylative coupling. [70] Acid chlorides are highly water sensitive, therefore a cross-coupling reaction of a terminal alkyne with acid chloride in aqueous media had not been reported until recently. In 2004, Li et al developed a highly effective direct coupling of acid chlorides with terminal alkynes catalyzed by PdCl 2 A C H T U N G T R E N N U N G (PPh 3 ) 2 /CuI together with a catalytic amount of sodium lauryl sulfate as the surfactant and K 2 CO 3 as the base to produce ynones with up to 99 % yield in water [Eq.…”

The thermoregulated ligand–palladium‐catalyzed carbonylative Sonogashira coupling of aryl iodides with terminal alkynes in water

“…Meanwhile, decreasing the palladium loading to 0.5 mol % in the carbonylative coupling reaction of 4-iodoanisole (1b) with 2a furnishes the corresponding alkynone 3ba in 86% yield (TON = 172; Table 3, entry 4), whereas for the previously reported PdCl 2 /PPh 3 /Et 3 N/H 2 O system to afford 3ba in 87% yield, the reaction needed to be carried out using 5 mol% of palladium catalyst. [48] Encouraged by the results presented above, we subsequently evaluated the reusability of the catalyst. As shown in Fig 2, the thermoregulated ligand-palladium catalyst is found to be effective for up to four consecutive recycles for the model reaction.…”