Organocatalytic Asymmetric Mannich Cyclization of Hydroxylactams with Acetals: Total Syntheses of (−)-Epilupinine, (−)-Tashiromine, and (−)-Trachelanthamidine
作者:Dipankar Koley、Yarkali Krishna、Kyatham Srinivas、Afsar Ali Khan、Ruchir Kant
DOI:10.1002/anie.201407185
日期:2014.11.24
cyclization between a hydroxylactam and acetal is described to provide fused, bicyclic alkaloids bearing a bridgehead N atom. Both aliphatic and aromatic substrates were used in this transformation to furnish chiral pyrrolizidinone, indolizidinone, and quinolizidinone derivatives in up to 89 % yield and 97 % ee. The total syntheses of (−)‐epilupinine, (−)‐tashiromine, and (−)‐trachelanthamidine also
羟基内酰胺和乙缩醛之间的不对称有机催化单锅曼尼希环化反应可提供带有桥头N原子的稠合双环生物碱。脂肪族和芳香族底物均用于该转化中,以高达89%的收率和97%的ee值提供手性吡咯烷酮,吲哚啶酮和喹喔啉酮衍生物。(-)-癫痫素,(-)-tashiromine和(-)-trachelanthamidine的总合成也证明了该方法的普遍性。