RESUMO
The "Staudinger ketene-imine reaction" between ketenes generated from natural O,N-protected trans-4-hydroxy-l-prolines and the N-benzyl-N-benzylideneamine led to mixtures of diastereoisomeric, enantiomerically pure pyrrolidine-derived spiro-beta-lactams with a relative cis configuration. These were transformed into the corresponding pyrroline-spiro-beta-lactams by means of treatment with a base and the new C=C double bond was submitted to a number of different reactions in order to evaluate its reactivity and obtain new polyheterocyclic enantiomerically pure spiro-beta-lactams.
Assuntos
Compostos Heterocíclicos/química , Prolina/química , Compostos de Espiro/química , beta-Lactamas/química , Antibacterianos/síntese química , Hidroxilação , Estrutura Molecular , Pirróis/química , Estereoisomerismo , beta-Lactamas/síntese químicaRESUMO
Carpanone has been stereoselectively synthesized in 55% yield and six steps from sesamol. The key step of the synthetic sequence is the direct introduction of the propenyl side chain via a Suzuki-Miyaura cross-coupling reaction. The subsequent Pd(II)-catalyzed oxidative coupling yields carpanone as a single diastereoisomer independently of the geometric configuration of the starting precursor. A new mechanism is proposed for this transformation.
