Stereocontrolled (3+2) cycloadditions between azomethine ylides and dipolarophiles: a fruitful interplay between
Abel de Cózar1, Fernando P Cossío
1Departamento de Química Orgánica I-Kimika Organikoa I Saila, Universidad del País Vasco-Euskal Herriko Unibertsitatea, Donostia International Physics Center (DIPC), San Sebastián-Donostia, Spain.
Abstract:
In this article we present recent developments in (3+2) cycloadditions with special emphasis on 1,3-dipolar reactions involving azomethine ylides and alkenes possessing electron withdrawing groups. It is found that there is not a general mechanism for these reactions since both concerted aromatic [(π)4(s)+(π)2(s)] mechanisms and stepwise processes involving zwitterionic intermediates can be found. These computational models can be extended to analyse the role of chiral catalysts in these reactions in order to understand the nature of the catalytic cycle and the origins of chiral induction.
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