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oai:mountainscholar.org:10217/2358622025-12-30T03:35:47Zcom_10217_100532com_10217_100000com_10217_100367com_10217_100303col_10217_100538col_10217_100368

DeMong, Duane Eugene, author Williams, Robert M., advisor 2022-11-28T17:46:50Z 2022-11-28T17:46:50Z 2003 https://hdl.handle.net/10217/235862 https://doi.org/10.25675/3.018852 An efficient and asymmetric synthesis of the non-proteinogenic amino acid (2S,3R)-capreomycidine is presented. The synthesis features a novel aluminum enolate-aldimine reaction with a chiral glycinate, which sets both stereocenters. A concise and high-yielding approach to the unnatural amino acid (2S,3S)-β-hydroxyornithine is also reported. The key step in this approach is a boron-mediated aldol reaction with a chiral glycinate. Additionally, the first asymmetric syntheses of α-formylglycine dimethyl and diethyl acetals are described. This two-step approach employs a novel titanium enolate of a chiral glycinate, followed by addition of the requisite trialkyl orthoformate to provide a single diastereomer of the glycinate adduct. Hydrogenolysis provides the optically pure acetal of α-formylglycine. Finally, the total synthesis of capreomyc in IB is described. The synthesis features the incorporation of the previously prepared (2S,3R)-capreomycidine. Additionally, the number of protecting group manipulations required in the synthesis has been greatly reduced by the utilization of asparagine in the peptide preparations as a masked precursor to diaminopropanoic acid. Conversion of the asparagine residue to the diaminopropanoic residue is accomplished by a Hofmann rearrangement. doctoral dissertations English eng Colorado State University. Libraries Catalog record number (MMS ID): 991018481299703361 QD431.D45 2003 2000-2019 Copyright and other restrictions may apply. User is responsible for compliance with all applicable laws. For information about copyright law, please see https://libguides.colostate.edu/copyright. Amino acids -- Synthesis The asymmetric synthesis of (2S,3R)-capreomycidine and the total synthesis of capreomycin IB Text Doctor of Philosophy (Ph.D.) Doctoral Chemistry Colorado State University This Item is protected by copyright and/or related rights (https://rightsstatements.org/vocab/InC/1.0/). You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s). open.access