Divergent Cyclization Reactions of Morita–Baylis–Hillman Carbonates of 2‑Cyclohexenone and Isatylidene Malononitriles

Zwitterionic dienolates
generated from Morita–Baylis–Hillman
carbonates of cyclohexen-2-one and a phenolic tertiary amine catalyst
underwent divergent cyclization reactions with isatylidene malononitriles.
A new [4 + 2] stepwise cyclization process was disclosed to deliver
complex bridged spirooxindoles after the initial δ′-regioselective
Rauhut–Currier-type reaction with N-methyl
electrophiles by the catalysis of β-isocupreidine, while spirooxindoles
incorporating an aromatic chromene motif were generated with N-MOM acceptors in the presence of α-isocupreine through
different domino transformations.

由环己烯-2-酮与酚类三级胺催化剂制备的 Morita–Baylis–Hillman 碳酸酯的季铵盐衍生物，在异亚甲基苹果腈的催化下经历了多种歧化环化反应。一种新型的[4 + 2]级联环化过程得以揭示，该过程在 β-异铜脒的催化作用下，首先通过 δ′-区域选择性 Rauhut–Currier 类型反应与 N-甲基亲电试剂进行初步反应，从而生成复杂的桥连螺氧杂吲哚；而在 α-异铜脒的存在下，通过不同的多米诺式转化，生成了含有芳香杂蒽结构的螺氧杂吲哚。