B(C ₆ F ₅ ) ₃ -Catalyzed Dearomative [2π+2σ] Cycloaddition of 1-Naphthols with Bicyclo[1.1.0]butanes

Converting planar arenes into C(sp³)-rich three-dimensional frameworks is an effective route to access bioisosteres of functional compounds. However, it remains challenging due to the inherent thermodynamic stability and kinetic inertness of planar arenes. In this work, we describe a simple, highly efficient, variable, and scalable method for the dearomative [2π+2σ] cycloaddition of 1-naphthols with bicyclo[1.1.0]butanes. Using this approach, 26 benzocyclohexanone-fused bicyclo[2.1.1]hexanes were obtained under mild reaction conditions in up to 99% yield with up to 19:1 dr.