UC San Diego

Since their seminal isolation as stable species in 1988, carbenes have become indispensable

ligands across a myriad of fields within chemistry. The origin of their exceedingly wide ranging

popularity is the energetic accessibility of these purely organic molecules’ frontier orbitals. In this

dissertation, these energetic boundaries will be pushed to new limits giving reactivity not previously

observed for stable carbenes. Indeed, by utilizing highly electrophilic carbenes, the isolation of P8 clusters

and a novel type of carbene P4 adduct was achieved. Additionally, coupling reactions of electrophilic

carbenes with a nucleophilic partner resulted in the formation of two rare examples of bent allenes, as

well as the isolation of the first carbene-carbene heterodimer. Furthermore, the synthetic

development and isolation of six-membered cyclic (alkyl)(amino)carbenes is discussed in detail. These

highly ambiphilic carbenes allow for the stabilization of a rare amino ketene, intramolecular C-H

activation of an unactivated methylene group, and have even provided evidence towards the description

of novel C-H···Se non-classical hydrogen bonding. Finally, the stability and electronic properties of a

pyrrolidinylidene derived remote N-heterocyclic carbene was investigated. This unique ligand opened into

an α,α,γ,γ-tetrasubstitued-2-allenyl ketimine in its free state, however the resulting allene was shown to

react as a carbene in the presence of electrophiles.