One-Pot Synthesis of Difluorobicyclo[1.1.1]pentanes from α-Allyldiazoacetates.

Rapid access to 2,2-difluorobicylco[1.1.1]pentanes is enabled from an α-allyldiazoacetate precursor in a one-pot process through cyclopropanation to afford a 3-aryl bicyclo[1.1.0]butane, followed by reaction with difluorocarbene in the same reaction flask. The modular synthesis of these diazo compounds affords novel 2,2-difluorobicyclo[1.1.1]pentanes that were inaccessible through previously reported methods. The reactions of chiral 2-arylbicyclo[1.1.0]butanes in the same manner generate altogether different products with high asymmetric induction, methylene-difluorocyclobutanes. Larger ring systems including bicyclo[3.1.0]hexanes are also rapidly furnished due to the modular nature of the diazo starting material.