Highly Efficient and Stereocontrolled Construction of 3,3′-Pyrrolidonyl Spirooxindoles via Organocatalytic Domino Michael/Cyclization Reaction

A wide range of structurally diverse 3,3′-thiopyrrolidonyl spirooxindoles bearing three contiguous stereogenic centers can be smoothly obtained via a domino Michael/cyclization reaction between 3-isothiocyanato oxindoles and 3-methyl-4-nitro-5-alkenyl-isoxazoles with commercially available quinine as the catalyst under mild conditions. The protocol is significantly characterized by high reactivity, a low catalyst loading (1 mol %), and an excellent diastereo- and enantioselectivity (up to >99:1 dr and 98% ee).

在温和反应条件下，以市售奎宁（quinine）为催化剂，通过3-异硫氰酸根合氧化吲哚与3-甲基-4-硝基-5-烯基异噁唑之间的多米诺迈克尔/环化串联反应，可顺利得到一系列结构多样、带有三个连续手性中心的3,3'-硫吡咯啶酮基螺环氧化吲哚（3,3′-thiopyrrolidonyl spirooxindoles）。该合成方法具有反应活性优异、催化剂负载量低（仅1 mol%），以及出色的非对映选择性与对映选择性（最高可达dr>99:1，对映体过量值达98%）的显著特征。