|
Title
|
Synthesis of new enantiomerically pure spiro-oxindolopyrrolizidines via a three-component Asymmetric 1,3-dipolar cycloaddition reaction of azomethine ylide
|
|
Type
|
Presentation
|
|
Keywords
|
azomethine ylide,chiral pyrrolizidines,spirooxindolopyrrolizidines, dipolarophiles,L-proline
|
|
Abstract
|
Because of wide distribution in nature and variegated biological activities, chiral pyrrolizidines alkaloids are very attractive synthetic targets [1]. The asymmetric 1,3-Dipolar cycloaddition reaction of azomethine ylides with olefins can be useful method for the synthesis of chiral pyrrolizidines[2]. On the other hand, oxindoles also are structural key moieties in many bioactive substances and it is interesting that systematic investigation has shown that if this moiety is joined to the pyrrolizidine ring through a spiro atom at C-3, the resulting compounds show an increased spectrum of biological activity [3]. There for we decided to synthesize a series of enantiomerically pure new spirooxindolopyrrolizidines using a three component reaction involving 1:3 dipolar cycloaddition reactions. In this report, at first we prepared chiral non-racemic dipolarophiles from the reaction of acrylates with pure oxazolidinone as achiral auxiliary. Then the reactions were carried out in a one-pot and proceeded through a 1,3-dipolar cycloaddition reaction of the chiral dipolarophiles with non-stabilized azomethine ylides which was generated in situ by the decarboxylative condensation of isatins with L-proline. After removal of oxazolidinone, chiral new spiro oxindolo- pyrrolizidines were obtained in high yield and high enantiomeric excess.
|
|
Researchers
|
Khosrow Jadidi (Fourth Researcher), Saadi Samadi (Third Researcher), Hamid Arvinnezhad (Second Researcher), Mohammad Javad Taghizadeh (First Researcher)
|