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
使用Grubbs卡宾(Cl(2)(Cy(3)P)(2)Ru = CHPh方便地取代的双β-内酰胺,吡咯烷基-β-内酰胺和哌啶基-β-内酰胺进行闭环甲基化中等大小的环,可与bis-2-azetidinone,吡咯烷基-2-azetidinone或哌啶基-2-azetidinone系统稠合。二烯烃环化前体可通过亚胺基2-氮杂环丁酮的[2 + 2]环加成,N-金属化的偶氮met胺从β-内酰胺环的位置1或3上带有一个额外的烯烃系链的光学纯的4-氧杂氮杂环丁烷-2-甲醛获得。 ylide [3 + 2]环加成反应,以及随后吡咯烷基氮原子的N-酰化反应,或通过2-氮杂环丁酮束缚的亚胺的aza-Diels-Alder环加成反应。在标准反应条件下,