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Application of 1,3‐azomethine ylides derived from α‐dicarbonyl compounds and L ‐proline to the synthesis of pyrrolizidines
Author(s) -
Felluga Fulvia,
Forzato Cristina,
Nitti Patrizia,
Pitacco Giuliana,
Valentin Ennio,
Zangrando Ennio
Publication year - 2010
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.371
Subject(s) - chemistry , phenylglyoxal , proline , enamine , amine gas treating , bicyclic molecule , component (thermodynamics) , stereochemistry , tandem , organocatalysis , organic chemistry , catalysis , medicinal chemistry , combinatorial chemistry , enantioselective synthesis , arginine , amino acid , biochemistry , physics , materials science , composite material , thermodynamics
AbstractThe reaction of 2,3‐butanedione, ethyl pyruvate, and phenylglyoxal with β‐nitrostyrene and L ‐proline in isopropanol at room temperature gives substituted pyrrolizidines, as a result of one‐pot three component reaction. On the contrary, a spiropyrrolizidine is formed from 1,2‐cyclohexanedione only when the reaction is carried out in refluxing isopropanol, whereas at room temperature, incorporation of the amine component into the products is not observed and bicyclo[3.2.1]octanones are formed, as a result of a tandem Michael‐Henry reaction. In this latter case, L ‐proline acts as an organocatalyst, although with modest enantioselectivity. The stereochemistry of the products is given and the mechanism of formation of products is postulated, on the basis of stereochemical arguments. J. Heterocyclic Chem., (2010).