Ligand strategies for green chemistry: Catalysts for amide reduction and hydroamination

by Megan L. Hovey

Institution: Iowa State University
Year: 2014
Keywords: Amide reduction; Hydroamination; Magnesium; Organometallic chemistry; Chemistry
Record ID: 2043975
Full text PDF: http://lib.dr.iastate.edu/etd/13907



This thesis describes the synthesis of a new class of mixed monoanionic cyclopentadienyl-bis(oxazoline) ligands and synthesis of new metal complexes. Two achiral ligands were synthesized: H3CC(C5H5)(OxMe2)2 (H{BoMCp}; OxMe2 = 4,4-dimethyl-2-oxazoline) and H3CC(C5HMe4)(OxMe2)2 (H{BoMCptet}). The chiral analogs were also prepared, H3CC(C5H5)(OxiPr)2 (H{BoPCp}, OxiPr = 4S-isopropyl-2-oxazoline) and H3CC(C5HMe4)(OxiPr)2 (H{BoPCptet}). These ligands support a wide variety of metals, including magnesium, zinc, titanium, and zirconium. {BoMCp}MgCH3, {BoMCptet}MgCH3, {BoPCp}MgCH3, and {BoPCptet}MgCH3 show excellent reactivity for catalyzing the hydroboration of ketones using pinacolborane. {BoMCp}Zr(NMe2)3, {BoMCp}MgCH3, and {BoMCptet}MgCH3 are also efficient catalysts for the hydroamination of aminoalkenes. This thesis also describes the catalytic reduction of amides to amines using pinacolborane as the reductant and catalytic amounts of [Mg]. ToMMgMe (ToM = tris(4,4-dimethyl-oxazolinyl)phenylborate is found to show excellent catalytic activity for the reduction of secondary and tertiary amides. Last, pyrene is functionalized with tertiary amine groups following a simple synthetic route from commercially available pyrene precursors. These pyrene compounds, including N-ethyl-N-(pyren-4-ylmethyl)ethanamine, N,N-diethyl-4-(pyren-4-yl)butanamine, and N,N-bis(pyren-4-ylmethyl)ethanamine were prepared to be adsorbed onto multi-walled carbon nanotubes as a catalyst.