Catalytic Formal [2π+2σ] Cycloaddition of Aldehydes with Bicyclobutanes: Expedient Access to Polysubstituted 2‐Oxabicyclo[2.1.1]hexanes

Abstract Synthesis of bicyclic scaffolds has attracted tremendous attention because they are playing an important role as saturated bioisosteres of benzenoids in modern drug discovery. Here, we report a BF 3 ‐catalyzed [2π+2σ] cycloaddition of aldehydes with bicyclo[1.1.0]butanes (BCBs) to access polysubstituted 2‐oxabicyclo[2.1.1]hexanes. A new kind of BCB containing an acyl pyrazole group was invented, which not only significantly facilitates the reactions, but can also serve as a handle for diverse downstream transformations. Furthermore, aryl and vinyl epoxides can also be utilized as substrates which undergo cycloaddition with BCBs after in situ rearrangement to aldehydes. We anticipate that our results…

• AV
  Alexander von Humboldt-Stiftung
• DF
  Deutsche Forschungsgemeinschaft

  Award: GRK 2678- 437785492
• WW
  Westfälische Wilhelms-Universität Münster
• L
  Leibniz-Gemeinschaft