论文部分内容阅读
关于含三个手性中心的螺环氧化吲哚γ-内酯的不对称合成鲜有报道.丙醛和氧化吲哚烯烃首先经有机催化进行不对称Michael加成反应;随后,在水/油两相条件下,Michael加成物经H_2O_2/K_2CO_3体系调节,进行α-羟基化/半缩醛化的串联反应;最后经氯铬酸吡啶(PCC)氧化,得到新颖的螺环氧化吲哚α-甲基仲康酸酯化合物.该合成策略具有条件温和、收率高(91%~98%)、对映选择性优秀(87%~95%)的特点,为手性多取代的螺环氧化吲哚γ-内酯的合成提供了一种简易的新方法.所有新产物均通过核磁共振谱和高分辨质谱对其结构进行确证.
Asymmetric synthesis of spiroxindole γ-lactone containing three chiral centers is rarely reported.Propane aldehyde and indoxyl oxide are first subjected to asymmetric Michael addition reaction by organic catalysis; Under the oil-two-phase conditions, the Michael adduct was subjected to a series of a-hydroxylation / hemiacetalisation reactions via H 2 O 2 / K 2 CO 3 system and finally oxidized with pyridinium chlorochromate (PCC) to give novel spiro epoxides Α-methyl-mesaconate compound, which has the characteristics of mild conditions, high yield (91% -98%) and excellent enantioselectivity (87% -95%), The synthesis of spiro epoxidation of γ-lactone provides a simple and new method, and all new products are confirmed by NMR and MS-MS.