GS4 Fascinations and Challenges in Natural Product Synthesis -breaking down "barriers"-   GS4-1. Synthetic Studies on Diterpenoid Pyrones, Nalanthalide, Sesquicillin and Candelalides.   GS4-2. Synthetic study of the Kopsia lapidilecta alkaloid Lapidilectam   GS4-3. Studies on Enantioselective Total Synthesis of (+)-Ophiobolin A   GS4-4. Novel Chitinase Inhibitors, Argifin and Argadin; Solid Phase Total Synthesis and Creation of Potent Inhibitors using Rational Molecular Design   GS4-5. Synthetic study of serotobenine～Aiming at the elucidation of a mystery serotobenine was isolated as a racemic form～   GS4-6. Studies toward the Total Synthesis of Azinomycin A