Innovation in Catalyst and Oxidative Amination Reaction Development for the Synthesis of Darobactin and Other Ribosomally Synthesized Post-translationally Modified Peptides (RiPPs)

点击翻译按钮获取中文摘要

Project Summary In this proposal we have outlined a plan to develop a new family of planar chiral indenyl Co, Rh, and Ir catalysts that will be broadly applicable in the development of new oxidative amination reactions. This represents a significant innovation in catalysis. Catalyst development is presented in the context of allylic C-H functionalizations, which represent a contemporary frontier of group IX metal catalysis, in which C-H functionalization relies on the innate reactivity of the C-H bond, and does not require a Lewis basic directing group. Our preliminary results support the hypothesis that the rhodium catalysts described in this proposal will enable a significantly expanded pool of viable nucleophiles and alkene substrates when compared to prior state-of-the-art palladium catalyzed allylic C-H functionalization. Mechanistic studies demonstrate that the parent RhCp* platform provides products via a common allylic acetate intermediate, obtained via oxidatively induced reductive elimination. These mechanistic investigations provide hypothesis driven 2nd generation catalyst and reaction designs to control regio- and enantioselectivity. Preliminary results demonstrate that the new catalyst platform is broadly applicable for enantioselective catalysis beyond allylic C-H functionalization reactions. The full development of these reactions represents a particularly significant advance in the synthesis of non-canonical amino acids, peptides, and amide containing natural products and pharmaceuticals. The new reactions and catalysts are developed for the synthesis of emerging ribosomally synthesized posttranslationally modified peptide (RiPP) natural products, discovered through bioinformatic analysis, and presenting novel structural motifs. In the long term, the realization of the chemistry described in this proposal will provide powerful new tools for drug discovery chemists to invent new pharmaceuticals.