连续双季碳螺环氧化吲哚拼接异噁唑类化合物的合成

Synthesis of Isoxazole-fused Bispirocyclic Oxindoles Featuring Two Adjacent Spiro Quaternary Stereocentres

以硝基异噁唑-3-烯氧化吲哚(1)作为基于给体和受体的3C合成子,与叔丁基酯-3-烯氧化吲哚(2),在碱性催化剂DABCO催化下发生Michael加成环化反应,获得10个新颖的连续双季碳螺环氧化吲哚拼接异噁唑类化合物3a~3j,产率为57%~70%,dr值为4/1~9/1,其结构经^(1)H NMR,^(13)C NMR和HR-MS(ESI-TOF)表征,并且经过单晶3f进一步确定了其结构。

The nitroisoxazole-3-eneindolinones(1)were used as a donor/acceptor-based 3C synthons for the first time.Ten novel isoxazole-fused bispirocyclic oxindoles(3a~3j)were synthesized via Michael addition and then cyclization reaction event of nitroisoxazole-3-eneindolinones 1 with methyleneindolinones(2)under DABCO as catalyst and room temperature conditions.The yields and dr of 3a~3j were 57%~70%and 4/1~9/1,respectively.The structures were characterized by ^(1)H NMR,^(13)C NMR and HR-MS(ESI-TOF),and further confirmed by X-ray crystallographic study of single crystal of 3f.