191592-48-0Relevant articles and documents
Synthesis of optically active pyrrolizidinediols: (+)-Heliotridine
Chamberlin,Chung
, p. 3653 - 3656 (1983)
A practical synthesis of the unsaturated pyrrolizidinediol (+)-heliotridine (5) is reported, starting from the readily available (S)-malic acid. The azabicyclo[3.3.0]octane ring system has been constructed via a stereoselective acyliminium ion cyclization directed by an acetoxy substituent. A ketene dithioacetal substituent in the cyclization precursor serves both as an efficient cationic cyclization terminator and later as a means of controlling double bound migration regioselectively into the correct position in the pyrrolizidine skeleton.
Regioselective reductions of various 3-aminosuccinimides; application to the synthesis of two heterocyclic systems
Briere, Jean-Francois,Charpentier, Patricia,Dupas, Georges,Queguiner, Guy,Bourguignon, Jean
, p. 2075 - 2086 (2007/10/03)
The synthesis of novel pyrrolo[3,2-c]isoquinolines is investigated starting from 3-aminosuccinimides. Various known routes leading to 3-aminosuccinimides were tested but a new approach via nucleophilic addition of arylalkylamines on maleimide gave better results. The regioselectivity of the reduction of these compounds was shown to depend on the degree of substitution of the concerned 3-aminosuccinimide. The hydroxylactams are formed in-situ, then converted into the ethoxylactams. The latter, after generation of an iminium salt, afforded the target pyrroloisoquinolines and two further derivatives of another new heterocyclic system: the 3,6-methano-2,5-benzodiazocine.
FREE RADICAL CYCLIZATIONS IN ALKALOID SYNTHESIS: (+)-HELIOTRIDINE AND (+)-HASTANECINE
Choi, Joong-Kwon,Hart, David J.
, p. 3959 - 3972 (2007/10/02)
Treatment of phenylthiolactams 5a-5f with tri-n-butyltin hydride and AIBN affords mixtures of reduction and cyclization products.Cyclization products partition between indolizidinones and pyrrolizidinones depending on the terminal alkyne substituent.When
