Now showing documents 1-6 of 6
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 ...
Preparation of conformationally restricted β2,2- and β2,2,3-amino esters and derivatives containing an all-carbon quaternary center
Abstract: β-Amino acids are routinely incorporated into peptidic drugs to increase their stability and to incur conformational biases. However, the synthesis of highly substituted β-amino acids still represents a great ...
General approach toward aspidospermatan-type alkaloids using one-pot Vilsmeier–Haack cyclization and azomethine ylide cycloaddition
Abstract: The development of a new one-pot reaction sequence afforded the tricyclic core of several aspidospermatan-type alkaloids from a linear, densely functionalized substrate. The key sequence features a highly ...
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 ...
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 ...