UC Berkeley

Organic Chemistry: Progress toward a total synthesis of the spiromeroterpenoid natural product asnovolin E is presented in Chapter 1 of this dissertation. Key features of our synthetic strategy include a Ti(III)-mediated cyclization of an epoxide, rhodium-catalyzed C−C bond cleavage of the resulting cyclobutanol, and the coupling of two carvone-derived cyclic fragments. This synthesis aims to provide efficient access to this biologically active natural product in a convergent fashion from an inexpensive chiral pool starting material, (R)-(−)-carvone. The synthesis and attempted coupling of several possible northern and southern fragments is described. In addition, the development of an acid-catalyzed Prins/semipinacol rearrangement cascade reaction of hydroxylated pinene derivatives which affords tricyclic fenchone-type scaffolds is reported. Quantum chemical analysis suggests that a post-transition state bifurcation exists following the Prins transition state, and the unusual selectivity for the fenchone-type scaffold is determined by nonstatistical dynamic effects.

Chemical Education: The remaining chapters of this dissertation focus on various student outcomes in two settings: organic chemistry courses and online laboratory environments. In Chapter 2, our investigation into how and why students make use of strategies related to metacognitive regulation during the process of solving organic chemistry problems is described. Student usage of planning, monitoring, and evaluation strategies in the specific context of completing complex predict-the-product problems was measured using think-aloud interviews and self-report instruments. Student usage of the same strategies in the more general context of completing assignments for their organic chemistry courses was also assessed using a similar self-report instrument. Results were compared between students with different levels of experience and between more and less successful problem solvers. In both contexts, a positive relationship was observed between metacognitive regulation and problem-solving performance or course performance. The results of this investigation support the importance of teaching metacognitive problem-solving strategies in organic chemistry courses and suggest several methods for the assessment and instruction of metacognition. In Chapter 3, the design and evaluation of choose-your-own-adventure-style video-based online experiments developed for use in 11 different courses across UC Berkeley and UC Santa Cruz is discussed. Students’ and instructors’ impressions of the online experiments and student learning outcomes in online and traditional laboratory courses were assessed using surveys, focus groups, and interviews. Though most respondents did not agree that online laboratory instruction was as effective as in-person instruction, the majority agreed that the online experiments were clear and easy to follow, interesting and engaging, and helpful for learning about laboratory techniques. Many also mentioned several benefits of online laboratory instruction, including greater flexibility in scheduling and an increased focus on conceptual learning. Assessments of student learning suggested that students who took the course online learned as much conceptually as students who had previously completed the course in person. These results highlight the positive and negative aspects of different modes of laboratory instruction, which could help inform the design of future laboratory experiences.