Suzuki Noriyuki

A novel multidentate ligand with an O,N,O-tridentate ligand moiety and an N-heterocyclic carbene (NHC) was synthesized. Its palladium complex, in which the NHC part coordinates to the palladium atom, was synthesized and structurally characterized. The O,N,O-part coordinated to an early transition metal such as titanium. The Ti-Pd heterobimetallic complex was observed in solution.

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.

With a number of biologically active members, 2‐aroylchromones are valuable synthetic targets. A direct route towards 2‐aroylchromones from 2‐(methylsulfonyl)chromones and aldehydes via NHC‐catalyzed C‐C bond formation was developed. Yields of the synthesized 2‐aroylchromones were up to 85%. Chromones with angioprotective or antibacterial properties were easily synthesized using the method developed. Additionally, the synthetic utility of the afforded chromones was demonstrated by using them to synthesize the anticancer compound wrightiadione and analogues of it.

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

A molecular editing strategy to construct quinoxalinones from chromones and benzimidazolylidene N-heterocyclic carbenes (NHCs) was developed. The C2 atoms of the chromones were incorporated into the quinoxalinones via ring expansion of the NHCs.