Unusual Fused Tricyclic 2-Azetidinones: Stereocontrolled Synthesis of Rigid Dipeptide Surrogates from β-Lactam-Tethered Imines via Sequential Cycloaddition/Ring-Closing Metathesis
作者:Benito Alcaide、Pedro Almendros、Jose M. Alonso、Moustafa F. Aly、María C. Redondo
DOI:10.1055/s-2001-14611
日期:——
The combination of [3 + 2] and [2 + 2]cycloaddition reactions of 2-azetidinone-tethered imines with ring-closing methatesis offers an asymmetric entry to a variety of unusual fused tricyclic 2-azetidinones bearing a bridgehead nitrogen atom, related to conformationally restricted peptidomimetics.
Asymmetric Synthesis of Unusual Fused Tricyclic β-Lactam Structures via Aza-Cycloadditions/Ring Closing Metathesis
作者:Benito Alcaide、Pedro Almendros、Jose M. Alonso、María C. Redondo
DOI:10.1021/jo026112l
日期:2003.2.1
one systems. The diolefinic cyclization precursors can be obtained from optically pure 4-oxoazetidine-2-carbaldehydes bearing an extra alkene tether at position 1 or 3 of the beta-lactam ring via [2 + 2] cycloaddition of imino 2-azetidinones, N-metalated azometine ylide [3 + 2] cycloaddition, and subsequent N-acylation of the pyrrolidinyl nitrogen atom, or through aza-Diels-Alder cycloaddition of