UCLA

Chapter one provides an overview of phosphine oxide catalysis, encompassing two strategies: redox-neutral and redox-driven phosphine oxide catalysis. It highlights some of the important examples reported in the literature, providing essential context for the subsequent chapter. Chapter two explores the development of innovative bridged [2.1.1] bicyclic phosphine oxides. These compounds are synthesized through a concise five-step process using readily available starting materials. Notably, we investigate silane-mediated reductions of bridged [2.1.1] bicyclic phosphine oxides and other known phosphine oxides, employing 31P NMR spectroscopy to assess their performances. Our findings reveal the superiority of these novel phosphine oxides over their current best-in-class counterparts, as they demonstrate a notably faster reduction rate at room temperature. Moreover, we showcase the practical application of these novel phosphine oxides in peptide coupling, offering a valuable complement to existing peptide synthesis methods. Chapter three delves into the realm of dealkenylative alkenylation. The dealkenylative alkenylation of alkene C(sp3)−C(sp2) bonds represents an underexplored avenue for C−C bond formation. The β-alkylated styrene derivatives (up to 64 examples) are synthesized by reacting easily accessible feedstock olefins with β-nitrostyrenes through ozone/FeII-mediated radical coupling, with high yield and good stereoselectivity. All the reactions are conducted under mild conditions, showcasing an impressive tolerance for a wide range of functional groups. Furthermore, we extend the utility of this methodology by demonstrating its efficacy in the synthesis of two significant compounds: the natural product iso-moracin and the pharmaceutical compound (E)-metanicotine.