Research

Considering Green Chemistry as a keyword, our organic synthesis laboratory are focusing on following topics.

1. Design of Chiral Organocatalysts

2. Amide Synthesis by Activaction of Carboxylic Acid Derivatives

3. Development of Organocatalyzed Asymmetric Reactions

Organocatalyst has become a great topic of scientific interest in both academic and industrial laboratories due to environmental friendless, simple operation, mild reaction conditions, and low cost. For example, L-proline, one of the chiral α-amino acid in nature, have been developed as strong bifunctional organocatalyst and employed in various asymmetric transformations. L-proline indeed made a big contribution to development of asymmetric organocatalysis and Benjamin List, who investigated its catalytic effect, won the Nobel Prize in chemistry in 2021.

We are working on design of bifunctional organocatalyst which is showing high catalytic performance in asymmetric transformations such as aldol reactions and Mannich reactions. To enhance reactivity and stereoselectivity, we are modifying basicity of amine functionality, acidity of acid functionality, rigidity and steric hinderance of backbone, and distance between acid and base functionalities.

Amide bond is one of the essential functional group in natural products, drugs, and agrochemicals. Furthermore, amide plays important role in peptides and various chemical materials such as nylon. Accordingly, efficient synthesis of amide derivatives is very attractive research topic for organic chemists. Amides are generally obtained by reaction of carboxylic acid with amines using coupling reagents. Transformation from ester or amide, however, is rare due to the difficulty of substrate activation. Although several methodologies are reported, metal reagents or harsh conditions are needed.

We are investigating development of efficient amide and ester activating methodology for amide bond formation under mild and environmentally friendly conditions. As a representative protocol, we are using hypervalent iodine(III) reagents to activate ester functionality which possesses phenol moiety as a potential activating group.

Chirality of organic molecule is important key of bioactivity of natural products, drugs, and agrochemicals. Indeed, about half of the drugs in current market is chiral products and the effect of each enantiomeric drug is completely different. To avoid unexpected side effect, it is clearly important to prepare both enantiomers and check the activity, respectively. Accordingly, asymmetric catalytic reaction have been highlighted as powerful tool to synthesize chiral target molecules efficiently.

We are developing novel asymmetric catalysis to prepare interesting chiral backbone which can be founded in bioactive compounds. In particular, various stereoselective methodologies for synthesizing N-heterocycles, for example pyrrolizine, pyrrolopiperazinones, azetidines, and isoxazolines, have been developed employing heteroatom nucleophiles in the presence of organocatalyst such as phase-transfer-catalyst and aminocatalyst.