Cascade Michael/aza-Michael Addition of α-Fluoroacetamides to p -Quinone Monoacetals Enables Monofluorinated Bridged Azabicyclo[3.3.1]nonanones

We report a diastereoselective synthesis of monofluorinated bridged azabicyclo[3.3.1]nonanones, a rare class of structurally privileged scaffolds, via a pyrrolidine-catalyzed double Michael addition of α-fluoroacetoacetamides to p-quinone monoacetals. The protocol was further extended to quinone imine ketals, providing access to functionalized fluorine-containing azabicyclo[3.3.1]nonane sulfonamides and α-aryl-α-fluoroacetamides. The method features broad substrate scope, excellent functional-group tolerance, gram-scale applicability, and straightforward derivatization, offering direct access to fluorinated bridged lactam frameworks.