Satoshi Yokoshima

A stereocontrolled total synthesis of (+)-vinblastine was accomplished, featuring preparations of the two indole units by means of a novel indole synthesis via radical cyclization of thioanilide, and a stereoselective coupling of these units.

Total synthesis of (-)-daphenylline, a hexacyclic Daphniphyllum alkaloid, was achieved. Construction of the tricyclic DEF ring system was initiated by asymmetric Negishi coupling followed by an intramolecular Friedel-Crafts reaction. Installation of a side chain onto the tricyclic core was carried out through Sonogashira coupling, stereocontrolled Claisen rearrangement by taking advantage of the characteristic conformation of the tricyclic DEF core, and the stereoselective alkylation of a lacton

The unique hexacyclic cagelike structure of (+)-gelsemine (1) has been accomplished. The first enantioselective total synthesis of this alkaloid features a facile construction of the bicyclo[3.2.1] core by means of two rearrangement reactions and the efficient formation of the pyrrolidine ring by an intramolecular Michael addition. Bn=Benzyl.

Abstract Stereocontrolled total synthesis of (+)-vinblastine ( 1 ) has been achieved using a novel radical-mediated indole synthesis developed in our laboratories. The isothiocyanate 18 , prepared readily from quinoline 17 , underwent a facile addition of the malonate anion to give 19 . The o -alkenylthioanilide 19 was then converted to indole 20 by radical cyclization and protection. (−)-Vindoline ( 2 ) was prepared from this key intermediate 20 in a highly efficient manner. The indole core of

So einfach wie möglich: Das immer noch stark nachgefragte Grippemedikament (−)-Oseltamivir-Phosphat (Tamiflu; siehe Schema) wurde ausgehend von Pyridin mithilfe billiger Reagentien synthetisiert, wobei die Zahl an Reinigungsschritten konsequent gering gehalten wurde. Die Syntheseroute umfasst eine asymmetrische Diels-Alder-Reaktion, eine Bromlactonisierung, eine Hofmann-Umlagerung und eine Dominoreaktion eines Bicyclo[2.2.2]-Systems in ein Aziridinintermediat. Supporting information for this art

A total synthesis of tetrodotoxin was accomplished. A Diels-Alder reaction between a known enone and a siloxy diene gave a tricyclic product, the steric bias of which was used to construct the remaining stereogenic centers. A nitrogen atom was introduced either by a four-step sequence involving a Curtius rearrangement, or a three-step sequence featuring a newly developed transformation of a terminal alkyne into a nitrile. Introduction of the guanidine moiety followed by the formation of the hete