Now showing documents 1-5 of 5
Intramolecular additions of various π-nucleophiles to chemoselectively activated amides and application to the synthesis of (±)-tashiromine
Abstract: Vilsmeier-Haack type cyclizations proved to be particularly efficient for generating parts of the polycyclic cores of many alkaloids, although only monocyclizations have so far been reported. With the goal ...
Addition of tethered nonaromatic carbon nucleophiles to chemoselectively activated amides
Abstract: In an effort to develop new ways of synthesizing polycyclic alkaloids, we successfully added silyl enol ethers, allylsilanes, and enamines to iminium ions generated from amides. Because of their higher oxidation ...
Synthesis of the tricyclic core of alkaloid securinol B using a cascade of vilsmeier-haack and mannich cyclizations
Abstract: The Securinega alkaloids are a family of approximately 20 tetracyclic compounds isolated from diverse Securinega, Phyllanthus, and Margaritaria species of the Euphorbiaceae plant family. Most of these alkaloids ...
Asymmetric total synthesis of (+)-virosine a via sequential nucleophilic cyclizations onto an activated formamide
Abstract: The first synthesis of tetracyclic alkaloid virosine A is reported. The natural alkaloid was prepared in only 13 steps, in an enantioenriched form. The azabicyclo[2.2.2]octane core was efficiently assembled using ...
Rapid assembly of quinolizidines via consecutive nucleophilic cyclizations onto activated amides
Abstract: A new approach to the synthesis of quinolizidines involving a cascade of nucleophilic cyclizations triggered by chemoselective amide activation is reported. Particular attention was given to the effect of the ...