The unique chemical structure of the FK-506 has attracted many synthetic organic chemists for its total synthesis. This review describes our completion of the total synthesis of (-) -FK-506. The biochemical and molecular events associated with lymphocyte activation are currently among the most well-studied in biology. These highly complex cells are of interest not only because they serve as a model system for elucidating events involved in transmitting signals between cell surface receptors and the nucleus, but also because of the important role that lymphocytes play in a variety of clinically relevant diseases. The observation that the major receptor for FK-506, FKBP, forms a complex with calcineurin, a calcium-calmodulin dependent phosphatase, opens new possibilities for our understanding of signal transduction and for the design of novel immunosuppressants.
Many nucleoside analogues, which lack 2'-substituents, have been known to be a useful compound as anticancer and anti-virus agents. On the other hand, synthesis of these derivatives utilizing the condensation reactions between sugars and nucleic bases have a difficulty in the stereoselectivity of these reactions. In this paper, our investigation on the condensation reactions with some 2-deoxysugars are discussed in the point of stereoselectivity. Transformations to 2', 3'-dideoxynucleosides and 2', 3'-didehydro-2', 3'-dideoxynucleosides are also described.
Numbers of events in the insect's life cycle are under the control of brain-neuropeptides. This review concerned with recent progress about chemical and biological studies on several brain-neuropeptides, such as prothoracicotropic hormone, eclosion hormone, pheromone biosynthesis activating neuropeptide, adipokinetic hormone and also insulin-related peptides, bombyxins, in Bombyx mori.
The taxane family is one of the most challenging synthetic targets due to their unique carbon skeleton coupled with the highly potent anticancer activities of a congener, taxol. We have developed a powerful methodology based on Lewis acid mediated direct eight-membered-ring cyclization for taxane B ring that offers a general route for natural taxane synthesis. The methodology provides simultaneous solution for the following three of the most difficult problems for taxane synthesis. 1) construction of the highly strained eight-membered B ring 2) stereoselective installation of the C-9 and C-10 oxygen functionalities 3) stereocontrol of the endo conformation.
Several higher terpenoids having 5-8-5-membered tricyclic frameworks have been isolated from various kind of natural sources. For the total synthesis of this class of compounds, it is desirable that the synthetic strategy has a stereochemical flexibility, since the stereochemistries involving a basic carbon skeleton are quite different depending on the origins. Our synthetic scheme involves three key-steps, which are the dimerization of two iridoids getting B-seco derivatives, the Cope rearrangement of the condensates controlling the stereochemistry of C-11, and the ring-closure forming the central 8-membered ring. We finally accomplished the method to control the transition states in the second step with which any stereochemical combinations of C-6, C-11, and C-14 can be constracted freely. The versatility of this synthetic methodology has been proved by the total syntheses of stereochemically different type of terpenoids, such as ceroplastol II, dictymal, cycloaraneosene, and the diterpene potion of plagiospirolide.