Thesis advisor: James P. Morken / This dissertation describes the development of two enantioselective methods of carbon-carbon bond formation. Chapter one discusses the development of an enantioselective Pd(0)-catalyzed conjugate addition of allylboronic acid pinacol ester to α,β-unsaturated methylidene ketones. Utilizing the same rationale for regio- and enantiocontrol as in the related enantioselective conjugate allylation of arylidene ketones, this method addresses the gap in technology by expanding the scope of the reaction to include alkyl-substituted enones. Chapter two examines the coupling of allyl electrophiles and allyl metal reagents. With computational insight into the reaction mechanism, a catalyst system was designed to control regioselectivity and enantioselectivity. Isotope labeling studies were carried out to probe the mechanism of the transformation. The reaction also proves to be diastereoselective when a substituted allyl boron reagent is employed. / Thesis (PhD) — Boston College, 2011. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.

This dissertation summarizes research efforts focused on the use of boron and transition metal halides to form new carbon-carbon and carbon-halide bonds. The boron halide mediated alkyne-aldehyde coupling reaction to generate 1,3,5-triaryl-1,5-dihalo-1,4-dienes was reinvestigated in an attempt to explain the stereochemistry observed during changing of both the mode of addition and the reaction temperature. Either (Z,Z)-1,4-dienes or (Z,E)-1,4-dienes can be the predominant product depending on reaction conditions used. This mechanistic investigation also led to the discovery of several novel reactions. These include the stereoselective preparation of (Z)-3-chloroallylic ethers from the reaction of alkenylboron dichlorides with aryl aldehydes in the presence of an amine; the titanium(IV) halide coupling of alkoxides and alkynes; the haloallylation of aryl aldehydes with boron trihalide using different allylmetals; and the base induced elimination of the haloallylated products to form 1,3-dienes. The results of these studies strongly imply a cationic mechanism. The new reactions described herein can be characterized as atom-efficient, environmentally friendly, and capable of generating the desired products in good to excellent yields.