Bicyclo2.1.1hexanes (BCHs) are important three-dimensional bioisosteres of substituted benzenes. Although mono- and fused-BCH scaffolds have been extensively studied, spiro-BCH derivatives remain relatively underexplored. Herein, we report a palladium-catalyzed tandem intramolecular annulation/strain-release 2σ + 2π cycloaddition between 5-allenyloxazolidine-2,4-diones and bicyclo1.1.0butanes (BCBs). This method provides efficient and concise access to a novel class of γ-lactam-spiro-BCH scaffolds in moderate to excellent yields. The transformation exhibits broad substrate scope, good scalability, and versatile downstream derivatization of the products.
Dong et al. (Wed,) studied this question.