Natural products are varieties of naturally occurring compounds that possess wide range of useful biological activities. Their intricate structures and activities are often the inspiration behind designs of medicinally significant molecules and new methodologies to perform chemical transformations. Through total synthesis of natural products, organic chemists discover how complex molecules behave in flasks and develop creative ways to build them. This dissertation describes findings and challenges from the effort towards total synthesis of portimine A, a complex marine natural product that is a highly selective inducer of apoptosis towards several cancer cells.

The first part of this dissertation details a new method in creating contiguous quaternary and tertiary carbon stereocenters through remote stereocontrol in Ireland-Claisen rearrangement. This new method enables stereocontrol in the rearrangement through a distant acetonide as an internal stereocontrol unit instead of transferring chirality from a chiral secondary alcohol, providing a rapid access to an extensively functionalized framework.

The second part of this dissertation describes efficacy of employing enyne metathesis in constructing cyclohexene diene motif commonly present in many members of cyclic imine family. This strategy is elegantly staged by the proceeding remote Ireland-Claisen rearrangement and is a convenient way to gain access to conjugated cyclic dienes.

The third part of this dissertation demonstrates the unprecedented use of N-heterocyclic carbene catalysis in complex macrocyclization. This strategy, with a large potential to be further optimized, is a useful method for large-membered macrocyclization baring various functionalities. The most recent discoveries on the total synthesis of portimine A following the successful macrocyclization are also discussed, and the remainder of synthesis is in progress.

Learning progressions are one of the most important curriculum and assessment design ideas to be introduced in the past decade. A well-constructed learning progression can incorporate the knowledge needed to define the “track” that students may or should be on. This can inform teachers about when to teach what to whom. For the development of sound learning progressions, researchers investigate how learning typically unfolds in a particular area of study, and should empirically test and validate it. A learning progression of Number Sense was developed in a research project, Special Education Learning Progressions in Math (SELPM). The progression includes hypothesized levels of achievement for grades K to 3 for four sub-domains of Number Sense: Place Value, Addition, Magnitude Comparison, and Transcoding. This research was concerned with the validation of the learning progression. The study used three student assessment data sets to investigate the validity of the proposed learning progressions using item response theory, specifically the Rasch model and its extension. This research consists of three validation studies – Phase I: Preliminary Study, Phase II: Testing Validity of Learning Progression, and Phase III: Validation of Alternative Learning Progression. Through the iterative validation process, this research aimed to provide an empirically-validated and theoretically-based Number Sense learning progression and a set of assessments for the education community

Engineers are needed more than ever to sustain our current life and maximize the best possible life for our future. From our everyday present lives, engineers work on powering our markets, offices, and homes to designing computer software. From what our future holds, engineers can develop efficient humanoid robotic systems to conduct surgical procedures, build renewable energy buildings and transportation sources, and predict meaningful political, medical, and financial information based on prior big data. Yet, in the United States, the field of engineering neither attracts nor maintains college students who were originally interested in pursuing it, particularly for minoritized students (Beering, 2007; National Science Foundation, 2021). Increasing and diversifying the number of engineers will contribute not only to better current and future living standards, but also bring new perspectives to solve the problems the nation faces. This dissertation research aims to address the critical issue of college students becoming uninterested or disengaged in engineering through YouTube videos to promote choice and persistence.

The dissertation consists of three separate, but connected papers that examine undergraduates’ choice and persistence in engineering using an alternative methodology of YouTube videos. Paper 1 focuses on engineering college students’ career values and the extent to which the discussion of their careers is associated with career values. There are two studies within this paper. The first study investigates students’ agentic (i.e., the importance of doing something in service of the self) and communal (i.e., the importance of doing something in service of others) career value themes in their written post-graduation responses after watching a YouTube video. I found career, personal development, and financial gains agentic career value themes as well as helping others and being family- oriented communal career value themes. The second study uses those career value themes to match achievement-related and interpersonal word categories to surveyed career values. I found significant associations between students’ word usage on their career and surveyed career values. Paper 2 examines transfer engineering undergraduates’ experiences filming engineering advice-related YouTube videos to community college students, in which we predicted that students experience the saying-is-believing effect. The saying-is-believing effect refers to how individuals are more likely to internalize a message if they advocate for it (Higgins & Rholes, 1978). This study identifies for important college students’ affective, cognitive, and behavioral engagement themes during their experiences creating the YouTube videos, in order to differentiate the different levels of the saying-is- believing effect. I found that students do differ in the extent to which they experience the saying-is-believing effect based on the different components of engagement. In particular, students’ positive affective experiences from creating YouTube videos may be the starting point to experiencing the saying-is-believing effect. Paper 3 takes a different perspective of the motivational intervention by focusing on the engineering community college students who watched the YouTube videos rather than those who filmed the YouTube videos. Students were able to choose from a library of videos from a diverse group of engineering transfer undergraduates. This study investigates the difference in engineering community college students’ course grades and subsequent engineering course enrollment between those who participated and those who did not participate in the intervention. I found that students who participated in the role model intervention leveraging YouTube had higher course grades and subsequent course enrollments in engineering compared to those who did not participate in the intervention.

Each of the three papers: (a) provides a greater understanding on how to support engineering college students’ choice and persistence; and (b) focuses on using YouTube videos as an alternative method to gain a more comprehensive picture on engineering undergraduates’ motivation. Using YouTube videos to understand students’ perceptions can help participants answer in a way that would minimize predetermined item choices and researchers’ expectations. This methodology can aid researchers and practitioners investigate engineering college students in a more naturalistic way. Incorporating a wide selection (or library) of YouTube videos from minoritized engineering college students can optimize the motivation of others who similarly identify, which can thus, increase the diversity in the labor force market.

In a nation of immigrants Los Angeles is increasingly a city of new immigrants. As of 1980,which is the most recent date for which good data are available, 20 percent of the population of the Los Angeles metropolitan area had been born abroad, mostly in Latin America and various Asian countries. Whereas New York historically has been the major port of entry for those immigrating to the U.S. from Europe, Los Angeles has been, and increasingly is, the major point of entry or those immigrating from Latin America and Asia. The result is a multi-ethnic, polyglot metropolis, with 142 languages spoken at home out of the 200 languages tabulated by the 1980 Census. As a consequence of this new immigration, Los Angeles has a more diverse ethnic mix than virtually any other city in the nation, and perhaps the world.

The pace of immigration, to Los Angeles as to the remainder of the country, has increased dramatically in recent years, starting in 1965, when past restrictive immigration policies were moderated (Muller and Espenshade, 1985). This new immigration wave shows few signs of abating as the 1980s draw to an end.

Why do these immigrants come? The motives for immigration are by now a familiar story. In the absence of political turmoil, individuals immigrate to improve economic opportunities for themselves and their children (Jackson 1969). California's strong economic growth as well as its proximity to the Pacific Rim have made it a natural entry point for immigrants from Asia and Latin America (McCarthy, 1983). Yet, once started, immigration has a self- sustaining quality. Growing ethnic enclaves can provide an important magnet for the continued flow of immigrants. At the micro level this occurs via chain migration, the movement of individuals within known social networks, usually the family. Information about economic opportunities can be quickly transmitted to distant relatives by previous immigrants. Patterns of chain migration can also reduce the costs of geographic mobility directly. Individuals who move within social networks often have jobs and housing waiting for them in the host country. At the macro level, the development of ethnic subeconomies can dampen the impact of fluctuations in the business cycle. In the 1970s, even though the Los Angeles economy declined relative to that of the rest of the state, immigrants were still coming, attracted by the opportunities afforded them in the various ethnic subeconomies (Light and Bonacich, 1985).

How do they fare? It is obvious that some groups have been much more successful than others. Selected socioeconomic characteristics for the 28 largest ethnic groups in the Los Angeles metropolitan area are shown in Table 1. Those of Asian, European, and Middle Eastern origin do substantially better than those of Latin American, African, or American Indian origin. Most striking, the first three groups have much higher proportions of adult males employed in administrative and professional occupations. Why is this so? The concern of this paper is to account for why some ethnic groups on average get better jobs than others. Subsequent papers will deal with other socioeconomic differences among ethnic groups in the Los Angeles area, and with the aggre- gate socioeconomic and political consequences of these group differences.