PhD Oral Exam - Fei Chen, Chemistry

When studying for a doctoral degree (PhD), candidates submit a thesis that provides a critical review of the current state of knowledge of the thesis subject as well as the student’s own contributions to the subject. The distinguishing criterion of doctoral graduate research is a significant and original contribution to knowledge.

Once accepted, the candidate presents the thesis orally. This oral exam is open to the public.

Abstract

Palladium catalysis is a salient synthetic methodology for carbon-carbon bond formation for which the classical procedures have been powerful tools in chemistry for decades. Due to certain limitations, alternative methods for palladium catalyzed cross couplings have been developed, rendering the approach more environmentally sustainable. Notably, the desulfinative cross coupling reaction avoids stoichiometric organometallic waste production. Furthermore, sulfinate salts are functionally versatile as they can act both as an electrophilic or nucleophilic cross coupling partner, and at the same time they are also bench stable and easy to handle. However, sulfinate salts can undergo self-disproportionation in solution limited its further synthetic applications. To overcome this issue, we propose to introduce a removable multiuse moiety to maintain the sulfinic acid. For this aim, we explore pyridine as a multipurpose option, due to its directing impact on palladium catalyzed ortho-halogenation, as well as it could protect the sulfinic acids, in order to providing access to a variety of useful scaffolds. This methodology also translates to ortho-deuteration for the synthesis of useful isotopic compounds with potential value for pharmaceutical research. After ortho-functionalization, the pyridine group can be removed to regain the sulfinic acid moiety for subsequent cross couplings. Combined, those approaches complement existing methodologies in accessing multi-functionalized arene systems.