Uranyl complexes of a large; compartmental N-8-macrocycle adopt a rigid, "Pacman" geometry that stabilizes the U-v oxidation state and promotes chemistty at a single uranyl oxo-group. We present here new and straightforward foutes to singly reduced and oxo-silyiated uranyl Pacman Complexes and propose mechanisms that account for the product formation, and the byproduct distributions that are formed using alternative reagents. Uranyl(VI) Pacman complexes in which one oxo-group is functionalized by a single metal cation are actiVated toward single-electron reduction. As such, the addition of a second equivalent of a Lewis acidic metal complex such as MgN"(2) (N" = N(SiMe3)) corms a uranyl(V) complex in Which both oxo-groups are Mg functionalized as a result of Mg N bond homolysis. In contrast, reactions with the less Lewis acidic complex [Zn(N")Cl] favor the formation of weaker U-O-Zn dative interactions, leading:to reductive silyiation of the tranyi oxo-group in preference to inetalation. Spectroscopic, crystallographic, and computational analysis of these reactions and of oxo-metalated products isolated by other routes have allowed us to propose mechanisms that account for pathways to metalation or Silylation of the exo-oxo group.