The cycloadditions of 2,2,2-trifluorodiazoethane with α-methylene-β-lactams were investigated. The reaction proceeded via a [3+2] cycloaddition mode under metal-free conditions, whereas the use of an iron catalyst enabled a cyclopropanation to occur. This protocol offers a facile access to a broad range of trifluoromethyl containing spirocyclic β-lactams.
Key words
2,2,2-trifluorodiazoethane - α-methylene-β-lactam - spirocyclic β-lactam - [3+2] cycloaddition - cyclopropanation