In the end of the 20th century, due to various advantages of organocatalysis including environmental friendliness, operational simplicity, mild reaction conditions, easy recovery etc., had led to its recognition as a powerful strategy for the establishment of practical organic synthetic methods. Over the two decades since then, tremendous effort has been devoted to the design of novel high-performance organocatalysts to realize unprecedented reactions including asymmetric transformations. In this review, our recent results on the rational design of various types of chiral phase-transfer catalysts with privileged structures, and their successful application to a wide variety of asymmetric transformations are described.
Modern sky surveys using large ground-based telescopes have discovered a variety of celestial objects. Prominent structures such as galaxies and galaxy clusters are found virtually everywhere, and their collective distribution forms the large-scale structure of the Universe. It is thought that all of the rich content in the present-day Universe developed through gravitational amplification of primeval density fluctuations generated in the very early phase of cosmic evolution. The standard theoretical model based on an array of recent observations accurately predicts the physical conditions in the early Universe, and powerful super-computers allow us to simulate in detail the formation and evolution of cosmic structure to the present epoch. We review recent progress in the study on the first generation of stars and blackholes. We focus on the physics of early structure formation, while identifying several key issues and open questions. Finally, we discuss prospects for future observations of the first stars, galaxies and blackholes.
2-Azahypoxanthine (AHX, 1) and imidazole-4-carboxamide (ICA, 2) were isolated from a fairy-ring-forming fungus Lepista sordida. AHX was converted into a metabolite 2-aza-8-oxo-hypoxanthine (AOH, 3) in plants. It was found out that these three compounds, named as fairy chemicals (FCs), endogenously exist in plants and are biosynthesized via a new purine metabolic pathway. FCs provided tolerance to the plants against various stresses and regulated the growth of all the plants. In addition, FCs increased the yield of rice, wheat, and other crops in the greenhouse and/or field experiments.
Glycosylation is an important posttranslational modification in mammals. The glycans of glycoproteins are classified into two groups, namely, N-glycans and O-glycans, according to their glycan-peptide linkage regions. Recently, O-mannosyl glycan, an O-glycan, has been shown to be important in muscle and brain development. A clear relationship between O-mannosyl glycans and the pathomechanisms of some congenital muscular dystrophies has been established in humans. Ribitol-5-phosphate is a newly identified glycan component in mammals, and its biosynthetic pathway has been elucidated. The discovery of new glycan structures and the identification of highly regulated mechanisms of glycan processing will help researchers to understand glycan functions and develop therapeutic strategies.