Nitrene transfer reactions by late transition metal complexes
Author(s)Hamilton, Charles W., Ph. D. Massachusetts Institute of Technology
Massachusetts Institute of Technology. Dept. of Chemistry.
Joseph P. Sadighi.
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This thesis presents nitrene transfer reactions that are catalyzed or mediated by late transition metal complexes. Sterically large, fluorinated supporting ligands are used to minimize potential side reactions. A new 1,10-phenanthroline ligand has been synthesized with 2,4,6-(CF3)3C6H2- groups in the 2- and 9-positions (1). A cationic copper(l) complex of 1 catalyzes nitrene transfer from N-(p-toluenesulfonylimino)phenyliodinane (PhlNTs) to the C-H bonds of 1,3-dimethoxybenzene in 63% yield. Altering the stoichiometry results in the formation of a different major product, N,N-bis(2',4'-dimethoxyphenyl)-p-toluenesulfonamide, in 33% yield. Treatment of a cationic copper(l) complex of 1 with p-nitrobenzenesulfonyl azide (NsN3) results in the formation of a rare mononuclear sulfonamido complex of copper(ll), 2. This complex is presumably formed via decomposition of a reactive sulfonimido complex of copper(lll). Although not a proficient nitrene transfer reagent to benzene, complex 2 is a precatalyst for nitrene transfer from NsN3 to benzene. Deprotonation of a palladium(ll) sulfonamido complex of 1 results in the formation of the first mononuclear sulfonimido complex of palladium,(cont.) 3. The sulfonimido ligand is bound in a K2-N,O chelate. This complex is a proficient nitrene transfer reagent to carbon monoxide, phosphines, and ethyl vinyl ether. A rhodium(lll) hydride chloride complex containing two N-heterocyclic carbene ligands, one of which is cyclometallated, is a convenient synthetic equivalent of a rhodium(l) chloride complex. Treatment of the rhodium(Ill) hydride with acetonitrile results in reductive elimination to form a rhodium(l) chloride complex. The chloride is readily abstracted by sodium azide to form a cationic rhodium(l) complex coordinated by two molecules of acetonitrile and containing an unbound azide. Upon exposure to UV light, this molecule undergoes cyclometallation to form a cationic rhodium(lll) hydride complex. The rhodium(lll) hydride chloride complex can be treated with oxygen to form a rhodium(lll) peroxide complex. The neutral peroxide complex has poor reactivity with trimethylphosphite and t-stilbene. However, a cationic rhodium peroxide complex oxidizes trimethylphosphite and t-stilbene at elevated temperatures.
Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Chemistry, 2007.Vita.Includes bibliographical references.
DepartmentMassachusetts Institute of Technology. Dept. of Chemistry.
Massachusetts Institute of Technology