Iron(III)-catalyzed consecutive aza-Cope-Mannich cyclization: synthesis of trans-3,5-dialkyl pyrrolidines and 3,5-dialkyl-2,5-dihydro-1H-pyrroles.
An efficient alkene aza-Cope-Mannich cyclization between 2-hydroxy homoallyl tosylamine and aldehydes in the presence of iron(III) salts to obtain 3-alkyl-1-tosyl pyrrolidines in good yields is described. The process is based on the consecutive generation of a γ-unsaturated iminium ion, 2-azonia-[3,3]-sigmatropic rearrangement, and further intramolecular Mannich reaction. Iron(III) salts are also shown to be excellent catalysts for the new aza-Cope-Mannich cyclization using 2-hydroxy homopropargyl tosylamine.
Instituto Universitario de Bio-Orgánica Antonio González, Departamento de Química Orgánica, Universidad de La Laguna, C/Astrofísico Francisco Sánchez 2, 38206 La Laguna, Tenerife, Spain.
Rubén M
RM
Carballo
Martín
M
Purino
Miguel A
MA
Ramírez
Víctor S
VS
Martín
Juan I
JI
Padrón
D001372:Aza Compounds / Q000737:chemistry*; D002384:Catalysis; D002712:Chlorides / Q000737:chemistry*; D003500:Cyclization; D005290:Ferric Compounds / Q000737:chemistry*; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry; D011759:Pyrrolidines / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
D001372:Aza Compounds; D002712:Chlorides; D005290:Ferric Compounds; D011758:Pyrroles; D011759:Pyrrolidines; C024555:ferric chloride