32548-24-6Relevant articles and documents
A new access to pyrrolizidine derivatives: Ring contraction of methyl (E)-[1,2-oxazin-3-yl]propenoates
Zimmer, Reinhold,Collas, Markus,Czerwonka, Regina,Hain, Ute,Reissig, Hans-Ulrich
, p. 237 - 244 (2008)
Nitrosoalkene 2 generated in situ from oxime 3 underwent smooth hetero Diels-Alder reaction with enol ethers 1 to afford 1,2-oxazine derivatives 4 bearing an exocyclic C=C bond. Methoxyallene 8 and 2 provided 6H-1,2-oxazine 10 in good overall yield. The exocyclic double bond of this type of 1,2-oxazines can be employed for addition reactions as demonstrated by dihydroxylation of 4a with potassium permanganate, smoothly delivering 1,2-diol 11. A reductive cascade reaction involving ring cleavage at the N-O bond followed by cyclization steps furnished pyrrolizidinone derivatives 12 in good yields. In the case of 12b this transformation proceeded with excellent stereoselectivity. Finally, the lactam moiety of 12 could be reduced with borane to provide the corresponding pyrrolizidine derivatives 19 in good yield. Georg Thieme Verlag Stuttgart.
Hydrogenation of pyrrolizin-3-ones; New routes to pyrrolizidines
Despinoy, Xavier L. M.,McNab, Hamish
experimental part, p. 4502 - 4511 (2009/12/25)
Pyrrolizin-3-ones (e.g.1) can be easily hydrogenated to their hexahydro (pyrrolizidin-3-one) derivatives in the presence of heterogeneous catalysts. Good diastereoselectivity (up to >97:3, depending on catalysts and solvent) can be achieved if the pyrroli
Radical Carboazidation: Expedient Assembly of the Core Structure of Various Alkaloid Families
Panchaud, Philippe,Ollivier, Cyril,Renaud, Philippe,Zigmantas, Sarunas
, p. 2755 - 2759 (2007/10/03)
A procedure for one-pot intermolecular radical addition of 2-iodoesters to terminal alkenes followed by azidation of the radical adduct has been developed. This sequential reaction represents an alkene carboazidation process. Its efficacy is demonstrated