Air-Stable Oxyallyl Patterns and a Switchable N-Heterocyclic Carbene.

Oxyallyl derivatives are typically elusive compounds. Even recently reported "stabilized" 1,3-diaminooxyallyl species are still highly reactive and have short lifetimes at room temperature. Herein, we report the synthesis and preliminary study of mesoionic pyrimidine derivatives that feature 1,3-bis(dimethylamino)oxyallyl patterns with an unprecedented level of stabilization. The latter are not only insensitive towards air and moisture, but they are also compatible with the formation of an ancillary stable N-heterocyclic carbene moiety. As the oxyallyl pattern is proton-responsive, it allows the reversible switching of the electronic properties of the carbene, as a ligand.