trans-2-Oxohexahydro-2H-furo[3,2-b]pyrroles (such as 2) are conformationally strained 5,5-fused ring systems and are potent human neutrophil elastase (HNE) inhibitors. A stereoselective synthesis is described based on intramolecular 5-exo-trig cyclisations of aldehyde acrylates 4 and 5 mediated by samarium(II) iodide to give predominantly trans-products 9 and 15. The n-propyl group in 15 is also generated with stereoselectivity for the desired β-isomer.
反式-2-氧代六氢-2H-
呋喃并[3,2-b]
吡咯(如 2)是构象受限的 5,5 融合环系统,是有效的人类中性粒细胞
弹性蛋白酶(HNE)
抑制剂。在
碘化钐(II)的介导下,醛
丙烯酸酯 4 和 5 发生分子内 5-外
三环反应,得到主要为反式产物的 9 和 15,从而实现了立体选择性合成。15 中的正丙基也可以立体选择性地生成所需的δ-异构体。