Intermolecular [2 + 2] Cycloaddition of 1,4-Dihydropyridines with Olefins via Energy Transfer

A highly regio- and diastereoselective visible-light-promoted [2 + 2] cycloaddition between readily available 1,4-dihydropyridines and olefins has been developed. This strategy is operationally simple and atom-economical and enables the construction of strained polysubstituted 2-azabicyclo[4.2.0]­octanes with three all-carbon quaternary centers with good functional group tolerance. These products can be easily converted to various structurally unique derivatives. The primary mechanistic studies demonstrated that the reaction proceeds through an energy transfer pathway.本研究开发了一种具有高度区域选择性与非对映选择性的可见光促进[2+2]环加成反应，可由易得的1,4-二氢吡啶类化合物与烯烃直接参与。该策略操作简便且原子经济性优异，能够以良好的官能团兼容性构建含三个全碳季碳中心的张力型多取代2-氮杂双环[4.2.0]辛烷产物。所得产物可便捷转化为多种结构独特的衍生物。初步机理研究证实，该反应经由能量转移途径进行。