摘要
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.
Chiral spirooxindole γ-lactones with three stereogenic centres are rare. An efficient asymmetric construction of novel spiro-fused 2-oxindole/α-methy-paraconnic ester is reported, which was offered via organocatalytic Michael reaction of propaldehyde and olefinic oxindoles, with subsequent H2O2/K2CO3 system-mediated α-hydroxylation/hemiacetalization cascade reaction under oil/water two-phase conditions, and final oxidative γ-lactonization by pyridinium chlorochromate (PCC). The presented strategy features mild reaction conditions, excellent yields (91%~98%) and enatioselectiveties (87%~95%), and accordingly constitutes a facile and new method for the synthesis of chiral multisubstituted spirooxindole γ-lactones. All structures of new products were confirmed by 1H NMR, 13C NMR and HRMS techniques.
出处
《有机化学》
SCIE
CAS
CSCD
北大核心
2017年第10期2776-2782,共7页
Chinese Journal of Organic Chemistry
基金
国家自然科学基金(No.21402176)资助项目~~