Candidate: Son Duc Tran

Degree of: Doctor of Philosophy

Department: Chemistry

Title: Synthetic Studies of 1,10-Phenathroline Derivatives as Novel Catalysis Ligans and their Application in Transition Metal-catalyzed Reactions

Committee: Dr. Elke Schoffers, Chair
Dr. James Kiddle
Dr. Jay Means
Dr. Marc Perkovic
Dr. Sylvia Rossbach

Date: Friday, November 11, 2005 1:00 p.m.- 3:00 p.m.
2902 Wood Hall

Abstract: The preparation of 1,10-phenanthroline derivatives entailed ring opening reactions of 1,10-phenanthroline epoxide as a key transformation, affording novel bidentate nitrogen ligands with new stereogenic centers in the 5- and 6-position. This research was concerned with [i] the epoxidation of 1,10-phen, [ii] epoxide ring opening reactions, [iii] the formation of trans-5,6-disubstituted-1,10-phenanthroline metal complexes, and [iv] applications of 1,10-phenanthroline derivatives in metal-catalyzed reactions, such as palladium-catalyzed allylic substitution and aminohalogenation reactions; Zinc-catalyzed direct aldol reaction and acetophenone reduction; Nickel-catalyzed Michael addition reaction.

[i] After thoroughly reviewing and modifying already published procedures, we were able to synthesize the key intermediate, 1,10-phenanthroline-5,6-epoxide, in high yield and quality by using commercial bleach (NaOCl) as oxidant.

[ii] The preparation of chiral trans-5,6- 1,10-phenanthroline derivatives was achieved through epoxide ring opening with various nucleophiles using Mg(ClO 4 ) 2 as an effective Lewis acid, and followed by the separation of stereoisomers via resolution.

[iii] Complication behavior towards transition metals was studied by reacting ligands with various Pd, Zn, Ru, and Ni sources. Complexes were studied via X-ray and computational analysis.

[iv] We tested novel phenanthroline derivatives for several applications, such as the palladium-catalyzed allylic alkylation of 1,3-diphenylprop-2enyl-acetate and aminohalogenation of a cinnamic ester; enantioselective reduction of ketones and direct aldol condensation promoted by ZnEt 2 . Nickel-catalyzed Michael addition reactions have also been tested for several 1,10-phenanthroline derivatives. Among all screened reactions, the direct aldol reaction was most successful and showed that C 2 diamine ligands gave very good enantioselectivity.

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