1449016-75-4Relevant academic research and scientific papers
Concise total syntheses of dipiperidine alkaloids virgidivarine and virgiboidine through Ru-mediated Ene-Ene-Yne ring rearrangement metathesis (RRM)
Kress, Steffen,Weckesser, Jochen,Schulz, Sabrina Renate,Blechert, Siegfried
, p. 1346 - 1355 (2013/04/10)
Herein, we report on the first enantioselective synthesis of the sparteine-type alkaloids virgidivarine (1) and virgiboidine (2). The stereoselective construction of the challenging dipiperidine core within 1 and 2 was realized by applying an intramolecular ene-ene-yne ring-rearrangement metathesis (RRM) protocol. In combination with this sequence, an unprecedented tandem metathesis/oxidation reaction was established. Subsequent to the RRM event, the Ru-alkylidene species was converted into the highly potent dihydroxylation catalyst RuO4 by the addition of NaIO4. This transformation rendered five sequential reactions that include an ene-ene-yne RRM/dihydroxylation/glycol cleavage in a one-pot procedure. This approach provides practical and general access to dipiperidines and piperidino-quinolizidines. Despite their wide use in organic and organometallic chemistry as well as their occurrence in biologically active natural products, methods are still lacking for the stereoselective synthesis of these motifs. Five@Once: A new method to access dipiperidine and piperidino-quinolizidine alkaloids was established within the total syntheses of virgidivarine (1) and virgiboidine (2). The key step includes a Ru-mediated intramolecular (tandem) ene-ene-yne ring-rearrangement metathesis/oxidation process, in which a sequence of five reactions occur in a single vessel with one catalyst source. Copyright
