New synthetic methods for spirolactams bearing an α-methylene-γ-butyrolactone or its analogous methylene-lactam have been developed. The allylation of γ-phenylthio-functionalized γ-lactams with 2-(acetoxy)methyl acrylamides was accomplished by using 2.5 equivalents of NaH to give the corresponding adducts in excellent yields. The remaining phenylthio group was substituted with a hydroxy group by treatment with CuBr, and the resulting γ-hydroxyamides were cyclized under acidic conditions to afford the corresponding methylene-lactam-fused spirolactams in high yields. On the other hand, methylene-lactone-fused spirolactams could be delivered from the allyl adducts in high yields through a sequential N-Boc protection/desulfinative lactonization.
我们开发了含有 α-亚甲基-γ-丁内酯或其类似亚甲基内酰胺的螺内酰胺的新合成方法。通过使用 2.5 等量的 NaH,完成了γ-苯硫基官能化的γ-内酰胺与 2-(乙酰氧基)甲基丙烯酰胺的烯丙基化反应,得到了相应的加合物,收率极高。用 CuBr 处理后,剩余的苯硫基被羟基取代,得到的 γ-羟基酰胺在酸性条件下环化,得到相应的亚甲基内酰胺融合的螺内酰胺,产率很高。另一方面,通过连续的 N-Boc 保护/脱硫内酯化反应,可以从烯丙基加合物中高产率地得到亚甲基内酰胺融合的螺内酰胺。