Intermolecular and Intramolecular α-Amidoalkylation Reactions Using Bismuth Triflate as the Catalyst
摘要:
Bismuth(III) triflate was found to promote the formation of stable cyclic N-acyliminium species in remarkable catalytic amounts (1 mol %). The alpha-amidoalkylation process seems to be effective in intermolecular and intramolecular manners leading to alpha-substituted lactams and heterocyclic systems containing azacycles, respectively. By comparing our results with those obtained with the classical Lewis acids as catalysts, it was evidenced clearly that the use of bismuth(III) triflate had been efficient for nearly all alpha-acetoxy lactams we used, except for N-acyliminium precursors bearing a sulfur atom. Also, the process seems to be easy, general, and clean, having diastereoselectivity comparable to protocols using classical Lewis acids and resulting in the formation of polyheterocyclic systems in good to excellent yields (64-99% in acetonitrile as solvent).
通过一锅逐步合成开发了一种简洁灵活的方案,用于组装结构多样的 1 H -吡咯并[3,4- b ]喹啉-1,3(2 H )-二酮(29 个实例,70–87% 产率) 。利用脂肪醇羟基作为导向基团合成具有潜在价值的奎宁稠合杂环,促进连续转化形成官能化氨基马来酰亚胺,然后进行I 2 -氧化串联环化。该路线涉及在温和条件下以一锅法形成多个新化学键(C=N、2C−N、CC−C)。