Asymmetric rhenium(I) dearomatization agents: The synthesis, reactivity, selectivity, and resolution of dihapto-coordinated aromatic complexes

Chapter 1 provides background information in the field of transition metal aromatic activation. Furthermore, a summary of the decade long study in the Harman lab on possible rhenium (I) systems as analogs to the pentaamminesomium(II) system is presented.; Chapter 2 illustrates the synthesis of the TpRe(CO)(L)(L_Ar) systems. This section serves as a useful reference text for the characterization and preparation of a wide variety of aromatic complexes.; Chapter 3 focuses on perhaps the most promising Re(I) system, namely the complex TpRe(CO)(MeIm)(η2-benzene). The compound has been proven to be a viable analog to pentaammineosmium(II). Furthermore, the rhenium system activates these bound compounds toward novel organic transformations (again, surpassing osmium in some cases).; Chapter 4 is the first of two selectivity studies, and provides rate data obtained from spin saturation experiments on a range of TpRe(CO)(L)(L _Ar) systems. The binding selectivities observed were found to be thermodynamically based. Furthermore, possible mechanisms for these interconversions are presented, and a high linear correlation was observed between the rates of intra- and interfacial conversion and the electronics of the metal (as varied by L).; Chapter 5, the second of the two selectivity studies, focuses again on the {lcub}TpRe(CO)(MeIm){rcub} system. A variety of olefins, aldehydes, and ketones with varying degrees of substitution were utilized to ascertain the steric environment around the metal center. Trends for NMR chemical shift as well as steric congestion have been observed.; Chapter 6 presents a methodology for resolving complex TpRe(CO)(MeIm)(η 2-benzene). Utilizing the knowledge gained from selectivity studies, a procedure involving α-pinene and a sterically hindered quadrant (a.k.a., the quadrant of death) on the metal was planned out and executed. The lability of (R)-α-pinene, when complexed to each metal enantiomer, was found to be significantly different, thus facilitating separation. The enantiomeric excess, measured with β-pinene, was high.; Chapter 7 looks toward the future, including a proposal for the development of a Group 6 dearomatization agent analogous to those developed for OS(II) and Re(I). Preliminary results on this project are also presented.