[
    {
        "id": "thesis:3784",
        "collection": "thesis",
        "collection_id": "3784",
        "cite_using_url": "https://resolver.caltech.edu/CaltechETD:etd-09262005-133922",
        "primary_object_url": {
            "basename": "Blackwell_he_1999.pdf",
            "content": "final",
            "filesize": 8482978,
            "license": "other",
            "mime_type": "application/pdf",
            "url": "/3784/1/Blackwell_he_1999.pdf",
            "version": "v2.0.0"
        },
        "type": "thesis",
        "title": "New synthetic applications for ring-closing metathesis and cross-metathesis employing well-defined ruthenium alkylidenes",
        "author": [
            {
                "family_name": "Blackwell",
                "given_name": "Helen Elizabeth",
                "clpid": "Blackwell-H-E"
            }
        ],
        "thesis_advisor": [
            {
                "family_name": "Grubbs",
                "given_name": "Robert H.",
                "clpid": "Grubbs-R-H"
            }
        ],
        "thesis_committee": [
            {
                "family_name": "Grubbs",
                "given_name": "Robert H.",
                "clpid": "Grubbs-R-H"
            },
            {
                "family_name": "Imperiali",
                "given_name": "Barbara",
                "clpid": "Imperiali-B"
            },
            {
                "family_name": "Gray",
                "given_name": "Harry B.",
                "clpid": "Gray-H-B"
            },
            {
                "family_name": "Barton",
                "given_name": "Jacqueline K.",
                "clpid": "Barton-J-K"
            }
        ],
        "local_group": [
            {
                "literal": "div_chem"
            }
        ],
        "abstract": "NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document.\n\nThe development of well-defined ruthenium alkylidene [...] (1) has revolutionized the application of the olefin metathesis reaction in organic synthesis. This thesis describes: (1) the application of ring-closing metathesis (RCM) to the synthesis of constrained cyclic peptides, (2) the conformational analyses of these peptide architectures, and (3) the development of new selective cross-metathesis (CM) methodology employing alkylidene 1.\n\nChapter 2 describes the initial application of RCM to the synthesis of cyclic amino acids and peptide [...]. Introduction of olefin functionality into peptidic structures proved straightforward, and treatment with ruthenium alkylidene 1 generated cyclic amino acids and dipeptides in excellent yields. Tetrapeptide diene analogs of naturally-occurring disulfide [...] proved to be robust substrates for RCM, and the macrocyclic olefin products could be prepared either in solution or on solid support.\n\nChapter 3 describes the application of RCM to the synthesis of macrocyclic hexapeptide [Beta]-sheets. The acyclic hexapeptide diene frameworks were modeled after hexapeptide disulfides reported to adopt [Beta]-sheet conformations. Treatment with ruthenium alkylidene 1, however, afforded only low yields of the desired 20-membered macrocycles: conformational analyses suggested that the hexapeptides adopted a helical rather than [Beta]-sheet conformation in the apolar solvents in which RCM was performed. These peptide systems were redesigned in Chapter 4 so that macrocyclization was favored when the peptides adopted a helical conformation. A series of macrocyclic heptapeptides were prepared in high yield via RCM which were shown to adopt [...]-helical conformations both in solution and in the solid state.\n\nChapter 5 describes new CM methodology involving the coupling of terminal olefins with symmetrically disubstituted olefins to generate heterodimeric cross-products in excellent yields and with high trans selectivity. CM was employed in an initial self-metathesis step to synthesize a variety of disubstituted olefins with diverse functionality, which were then further processed in the CM with terminal olefins. Finally, a new CM application was introduced involving the metathesis of acrolein acetal derivatives with terminal olefins to generate [...] aldehydes.\n",
        "doi": "10.7907/XBZ4-CV61",
        "publication_date": "1999",
        "thesis_type": "phd",
        "thesis_year": "1999"
    }
]