Date of Award
Doctor of Philosophy (PhD)
William A. Donaldson
Chae S. Yi
In an effort to make diverse molecular complexity from simple hydrocarbons, tricarbonyl(cyclohexadienyl)iron(+1) cation was prepared in two steps from 1, 3-cycloxehadiene. Reactivity of the symmetric iron cation with heteroatom nucleophiles and stabilized carbon nucleophiles was studied. Nucleophilic attack of potassium phthalimide at the dienyl terminus of the cation followed by oxidative decomplexation with Ce4+ provided the ligand N-(2,4-cyclohexadiene-1-yl)phthalimide. A series of stereochemically diverse polyhydroxyl aminocyclohexane "aminocyclitols" derivatives and a number of racemic and optically active hydroxy-and polyhydroxy 1,3-diaminocyclohexane derivatives have been synthesized from N-(2,4-cyclohexadiene-1-yl)phthalimide. The relative stereochemistries of the compounds ware assigned on the basis of the 1H NMR data as well as X-ray single crystal diffraction analysis.
In a similar attempt tricabonyl(η5-6-styrylcyclohepta-2,4-diene-1-yl)iron(+1) cation was synthesized in three steps from 1, 3, 5, 7-cyclooctatetraene. Reactivity with various nucleophiles was studied. Nucleophilic attack of lithium dimethylallyl malonate at the less hindered pentadienyl terminus of the cation, decomplexation by Ce4+ followed by rearranged ring closing metathesis using 1st generation Grubbs catalyst gave skeletally unusual (5E, 7Z, 9Z)-dimethylbicyclo[4.4.1]undeca-5,7,9-triene-2,2-dicarboxylate.
Reaction of potassium phthalimide with tricabonyl(η5-6-styrylcyclohepta-2,4-diene-1-yl)iron(+1) cation in a similar fashion, followed by decomplexation with Ce4+ gave racemic 2-(1S, 6R)-6-((E)-styryl)cyclohepta-2, 4-diene-1-yl)isoindoline-1, 3-dione. Asymmetric dihydroxylation of the iron free ligand with ADmix-β followed by cycloaddition with singlet oxygen generated two optically active separable diastereomeric endoperoxides, which led to the synthesis of a number of racemic and optically active functionalized endoperoxides.