Synthesis and Applications of 3-Methylene-4-(trifluoromethyl)azetidin-2-ones as Building Blocks for the Preparation of Mono- and Spirocyclic 4-CF3-[beta]-Lactams

3-Methylene-4-(trifluoromethyl)azetidin-2-ones were efficiently prepared from the corresponding 3-oxo-4-trifluoromethyl-[beta]-lactams and successfully evaluated as novel building blocks in organic synthesis. In particular, Michael additions, electrophilic additions, and cycloadditions were applied to allow easy access to a broad variety of stereodefined mono- and spirocyclic 4-CF3-[beta]-lactams as useful synthetic intermediates en route to a variety of biologically relevant CF3-functionalized target structures.