Thesis advisor: Amir H. Hoveyda / Chapter 1. Catalytic olefin metathesis has developed into a powerful tool in the arsenal of the synthetic chemist as a quick and reliable method to build complexity in biologically active molecules. One particular subset of this class of reactions, catalytic olefin cross-metathesis, has seen great strides within the last decade. Using recently reported well-defined catalysts, chemists have been able to synthesize olefins in a stereoselective fashion via this reaction in a laboratory setting. While many classes of Z olefins have succumbed to this transformation, one class of olefins that has not been synthesized in a selective manner is that of Z-unsaturated esters, precious motifs found in a myriad of natural products. Traditional preparations of Z-acrylates and Z-dienoates are presented drawing examples from both total syntheses as well as method development reports. Chapter 2. A catalytic olefin cross-metathesis reaction utilizing E-dienoates as substrates is presented. A large variety of functionalized (E,Z)-dienoates are prepared in high yields and high stereoselectivities. This method has many advantages over more common methods of making these motifs, such as a wider substrate scope and the ability to be performed at ambient temperature. / Thesis (MS) — Boston College, 2015. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Chemistry.