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Influence Of Tethered, Axially Coordinated Ligands On Rh(Ii,Ii)-Catalyzed Carbene Transfer Reactions, Cristian E. Zavala
Influence Of Tethered, Axially Coordinated Ligands On Rh(Ii,Ii)-Catalyzed Carbene Transfer Reactions, Cristian E. Zavala
Doctoral Dissertations
Dirhodium (II,II) paddlewheel complexes have become ubiquitous in diazo-mediated carbene transfer reactions. The Rh(II,II)-carbene intermediate is capable of a large variety of transformations such as cyclopropanation, C-H and X-H (O, N, S, Si, B) insertion reactions, cyclopropenations, and ylide transformations. Cyclopropanation reactions resulting in the formation of functionalized cyclopropane structures has always been a major focus in Rh(II,II)-carbene chemistry. Improvements on catalytic performance in cyclopropanations has largely focused on the modification of the bridging ligands and has resulted in Rh(II,II) catalysts that exhibit high reactivity and selectivity in cyclopropanation reactions. However, high enantio- and diastereoselectivity is not easily achieved with …
Fine Tuning Rhii Complexes With Tethered, Axial Coordination: Structural Studies And Application To Diazo-Mediated Cyclopropanation Reactions, Derek Cressy
Doctoral Dissertations
The cyclopropane moiety is an attractive synthetic target due to its application in pharmaceuticals and medicinal research. One effective strategy involves the formation of metal carbenoid species from diazo reagents. The carbenoid then reacts with an olefin substrate to generate the cyclopropane ring. Of the metal complexes that can facilitate this reaction, dirhodium(II) paddlewheel complexes are arguably the most prevalent catalysts. This is because modification of the bridging ligands enables control to be exerted over the catalyst’s chemoselectivity and enantioselectivity. Exploiting the axial site as a control element is often overlooked as strongly coordinated Lewis bases inhibit catalysis. Despite this, …
Investigating The Effects Of Tethered, Axial Lewis Base Coordination On Rhodium(Ii) Paddlewheel Complexes, William A. Sheffield
Investigating The Effects Of Tethered, Axial Lewis Base Coordination On Rhodium(Ii) Paddlewheel Complexes, William A. Sheffield
Masters Theses
Dirhodium(II) paddlewheel complexes are highly renowned for their use in diazo decomposition to form a metallic-carbenoid species. This species has been used for a diverse range of chemical transformations including cyclopropanation, cycloproprenation, C-H functionalization, and X-H (Si, S, O, N) insertion reactions. Modulation of these catalysts traditionally involve the exchange of bridging ligands which have profound effects on the catalyst’s reactivity, chemo, and enantioselectivity. Recent interest has turned towards to modifying the axial sites present in the complex as an additional means of modulating catalytic activity. These sites normally serve as the active site of the catalyst, but coordination of …