Rikukawa Masahiro

Background: Developing environmentally benign processes, such as organic reactionsconducted in water, is desired from the view of sustainable technology. Concerning the palladiumcatalyzedborylation reactions of aryl halides in water, only a few examples have been reported. Objective: This study aimed to develop efficient methods for palladium-catalyzed borylation reactionsof aryl halides in water, not only increasing product yields but also extracting products withless organic solvents. Methods: We adopted polymer surfactants, such as diblock copolymers that consist of poly(Nisopropoylacrylamide)and a hydrophilic segment, and a poly(ethylene glycol)-based polymer thatconsists of poly(ethylene glycol) chain and 4-chloromethylbenzyl moiety. Results: Reactions using these polymers gave the borylation products in significantly higher yieldsthan that in pure water. The efficiency of the extraction process for the products from the reactionmixtures was evaluated, indicating that the polymer micelles enabled separation processes with lessorganic solvent. Conclusion: Applying polymer surfactants increased the product yields in Pd-catalyzed borylationof aryl halides, and it enabled the extraction of the products from the aqueous reaction mixture moreefficiently.

Pd complexes covalently tethered on thermoresponsive polymer catalysed coupling reactions in water.