Enantioselective Isothiourea-Catalysed Michael–Michael–Lactonisation Cascade Reaction for the Synthesis of δ-Lactones and 1,2,3,4-Substituted Cyclopentanes
作者:Andrew Smith、Emily Robinson、Aileen Frost、Pilar Elías-Rodríguez
DOI:10.1055/s-0036-1588636
日期:——
β-unsaturated acid chlorides. Subsequent reaction with enone-malonates gave access to δ-lactones in 20–64% yield, 72.5:27.5 to 95:5 er and 81:19 to >95:5 dr. Additionally, application of a ring-opening protocol yielded 1,2,3,4-substituted cyclopentanes in 28–77% yield, 76:24 to 98:2 er and 86:14 to >95:5 dr. Interestingly, the highest er was observed at high reaction temperatures, with 70 °C proving optimal
献给教授迪特尔·恩德斯在他70之际个生日 抽象的 该手稿描述了在Michael–Michael–内酯化级联过程中,α,β-不饱和酰基铵中间体的应用,以提供δ-内酯。将异硫脲催化剂HyperBTM添加到α,β-不饱和酰氯中可实现α,β-不饱和酰基铵中间体的产生。随后与烯酮丙二酸酯反应可得到δ-内酯,收率20-64%,72.5:27.5至95:5 er和81:19至> 95:5 dr。此外,开环方案的应用产生了1,2,3,4-取代的环戊烷,产率为28-77%,76:24至98:2 er和86:14至> 95:5 dr。有趣的是,在较高的反应温度下观察到最高的er,事实证明最佳温度为70°C。通过进行Eyring分析研究了这种效果, 该手稿描述了在Michael–Michael–内酯化级联过程中,α,β-不饱和酰基铵中间体的应用,以提供δ-内酯。将异硫脲催化剂HyperBTM添加到α,β-不