1. Development of Efficient Cyclization Methods: Efficient synthetic methods for five-, six-, and seven-membered rings have been developed, and the syntheses of polycyclic structures using those compounds are under investigation. We are currently working on the Mn(III)-catalyzed oxidative hetero-aromatic cyclization for the syntheses of furan, pyrrole, indole, piperazinones.

2. Chemistry of Isoprenoid: Isoprenoid can be classified into terpenoid, carotenoid, and steroid. We have developed various bi-functionalized C₅ prenyl building blocks that can be efficiently used in the chain-extension processes for making various isoprenoid natural products. We adopted the Julia Sulfone protocol in C–C bond formation, which would give polyprenyl or polyene structures depending on the sulfone elimination process. Carotenoid natural products have been nicely assembled using our C₁₀ bis(chloroallylic) sulfide, or C₁₀ dialdehyde, or even C₂₀ diphosphonate. We extended this strategy to make other important carotenoid compounds. We further pursue the synthesis of terpenoid and steroid compounds by the combined use of our cyclization and chain-extension strategies. Followings are the carotenoid compounds that we have made so far: Vitamin A, Vitamin K, Tretinoin, Isotretinoin, Tocoretinoate, b-carotene, Lycopene, Lycophyll, Nor-Bixin, Crocetin, Zeaxanthin, Astaxanthin, Canthaxanthin, Coenzyme Q-10, and Abscisic acid.

3. Conducting Molecular Wires: Based on our methods of the carotenoid synthesis, we were able to construct the conjugated polyene chains with variable lengths. This conjugated polyene chains, which conduct electrons, can be stabilized by attaching phenyl substituents to the chain. We are preparing various organic conducting wires with different resistances. We are going to build up various molecular electronic circuits with diverse conductance

 4. Biomass conversion: Efficient conversion methods of sugars into useful platform chemicals such as 5-hydroxymethylfurfural (5-HMF) and 5-hydroxymethylpyrrole-2-carbaldehydes (pyrralines) are being investigated. A bis(sulfonic acid)-ionic liquid was utilized for fructose conversion to 5-HMF. The optimal condition using DMSO and oxalic acid transformed glucose and primary amines into pyrralines. This one-pot conversion of sugars into pyrralines is being applied to the total synthesis of biologically active natural products, (–)-Hanishin, Lobechine, and Magnolamide. Biomass conversion of ribose into sustainable platform chemicals as intermediates for new drug synthesis is underway