Hayes, Paul

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https://opus.uleth.ca/handle/10133/4922

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Browsing Hayes, Paul by Subject "Rhodium"

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    Rhodium-mediated assembly of new heterocycles: from borylenes to oxaboroles
    (Wiley, 2025) Hsiang, Shou-Jen; Hayes, Paul G.
    Base-stabilized rhodium borylene complex κ2-L(CO)Rh(BMes), 2; κ2-L=κ2-NN’-Rh,κ1-N−B-(2,5-[iPr2P=N(4-iPrC6H4)]2-N’(C4H2)−); Mes=mesityl, reacts with a series of alkynes (PhC≡C—R; R=Ph, Me, CO2Et, H) to yield unique structures whereby the alkyne has regioselectively added across boron and the carbon atom of a CO ligand. The resulting complexes, LRh[C(O)C(Ph)C(R)B(Mes)], 3R, react with additional CO to afford cycle-containing products, L(CO)Rhmathematical equation ), 5R, that ultimately release highly functionalized organic heterocycles of the form mathematical equation =NPipp (Pipp=4-iPrC6H4), 6. These oxaboroles, which were assembled from a primary hydroborane, CO, an alkyne, and an azide-generated NPipp, are structurally analogous to two of the five boron-containing therapeutics approved by the FDA.
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    Rhodium-mediated dehydrogenation of hydroboranes and group 14 compounds: base-stabilized silylene and germylene complexes vs. transmetalation
    (Wiley, 2024) Hayes, Paul G.; Hsiang, Shou-Jen
    Monocarbonyl rhodium complex LRh(CO), 1, which is stabilized by a pyrrole-based bis(phosphinimine) pincer ligand (L=k3- NNN’=2,5-[iPr2P=N(4-iPrC6H4)]2-N’(C4H2)􀀀 ), serves as a versatile platform for the dehydrogenation of group 14 substrates. Reaction with primary and secondary silanes and germanes (MesSiH3, Et2SiH2, Ph2GeH2, tBuGeH3; Mes=mesityl) liberates H2 and yields base-stabilized tetrylene compounds of the form k2- L(CO)Rh(ER2) (E=Si: R=Mes, H, 2; R=Et, 5; E=Ge: R=Ph, 6; R= tBu, H, 8). The “:ER2” fragment in these species bridges between the rhodium center and a phosphinimine donor. Preliminary reactions between pinacol (Pin) and k2-L(CO)Rh(ER2), E=Si, Ge, indicate that such complexes can serve as silylene and germylene synthons, releasing :ER2 and catalytically generating PinER2. In contrast, combination of complex 1 and MesGeH3 does not yield the anticipated dehydrogenation product, but rather, transmetalation similar to that observed upon reaction between 1 and 3,5-dimethylphenylborane prevails.