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  • Development of Methods for Stereoselective Carbon-Carbon Bond Formation

    Creator:
    Wu, Zhenhua
    Abstract:
    Three distinct methods to achieve the stereoselective synthesis of carbon-carbon bonds were investigated, encompassing: (i) the formation of axially chiral biaryl molecules by enantioselective Suzuki cross-coupling, (ii) the synthesis of α-phenylalkylboronic esters by enantioselective chain extension, and (iii) the stereospecific synthesis of alkenes by eliminative cross-coupling of enantioenriched sp³-hybridized carbenoids....
    Resource Type:
    Dissertation
    Full Text:
    : ______________________________________________________ Paul R. Blakemore Three distinct methods to achieve the stereoselective synthesis of

  • Analysis of the mechanism of sulfoxide-lithium exchange and the reactive intermediate in stereospecific reagent-controlled homologation (StReCH)

    Creator:
    Hoyt, Amanda
    Abstract:
    The stereospecific reagent-controlled homologation (StReCH) of boronic esters with enantioenriched carbenoid species generated in situ by the addition of organolithium initiators to stereodefined α-chloroalkyl aryl sulfoxides was previously reported. The reaction of an organolithium with an α-chloroalkyl aryl sulfoxide ostensibly generates an α-chloroalkyllithium via sulfoxide-lithium exchange; however, the true nature...
    Resource Type:
    Masters Thesis
    Full Text:
    : Paul R. Blakemore The stereospecific reagent-controlled homologation (StReCH) of boronic esters

  • Stereocontrolled Synthesis of Allenes by Eliminative Cross-Coupling of Carbenoids

    Creator:
    Cao, Yang
    Abstract:
    The bimolecular reaction of two carbenoid species resulting in the formation of a carbon-carbon double bond (pi-system), referred to herein as carbenoid eliminative cross-coupling (CEXC), involves a series of three fundamental steps: (i) ate-complex formation (transmetalation), (ii) 1,2-metalate rearrangement, and (iii) beta-elimination. All three steps are stereospecific and so the...
    Resource Type:
    Dissertation
    Full Text:
    Paul R. Blakemore The bimolecular reaction of two carbenoid species resulting in the formation

  • Total Synthesis of Isotopologues of Xanthohumol and its Congeners for Biological Studies

    Creator:
    Plagmann, Layhna S.
    Abstract:
    Xanthohumol [XN, (E)-6´-methoxy-3´-(3-methylbuten-2-yl)-2´,4´,4´´-trihydroxychalcone], the principal prenylated chalcone from hops, and its 2,3-dihydro- (DXN) and O6-desmethyl-2,3-dihydro- (DDXN) congeners, are of potential utility for the amelioration of metabolic syndrome; however, their complex bioactivity profiles cannot be properly studied and understood without access to appropriately produced synthetic materials. In the first part of...
    Resource Type:
    Masters Thesis
    Full Text:
    Isotopologues of Xanthohumol and its Congeners for Biological Studies Abstract approved: Paul

  • Development of Carbenoid Eliminative Cross-coupling for the Stereocontrolled Synthesis of Trisubstituted Alkenyl Moieties Within Styrenes and 1,3-Dienes

    Creator:
    Tanpure, Subhash D.
    Abstract:
    Traditional approaches for the direct preparation of alkenes are unable to fully control either the stereochemical configuration of the carbon-carbon double bond or else the regiochemistry of the substituents surrounding it. The recently introduced concept of carbenoid eliminative cross-coupling (CEXC) offers a remedy to these deficiencies by providing for a...
    Resource Type:
    Dissertation
    Full Text:
    : ______________________________________________________ Paul R. Blakemore Traditional approaches for the direct preparation of alkenes are

  • Synthesis of novel ambifunctional atropisomeric 2,2',6,6'-tetrasubstituted biphenyls and investigation of their properties and organocatalytic activity

    Creator:
    Sephton, Mark Alan
    Abstract:
    Ambifunctional axially chiral 2,2',6,6'-tetrasubstituted biphenyls containing nucleophilic (or basic) functional groups juxtaposed with hydrogen-bond donors were synthesized and their properties studied. Applications for the prepared biaryls as potential organocatalysts for enantioselective carbon-carbon bond forming reactions were examined. Processes investigated included: aldol, Michael, nitroaldol (Henry), and Baylis-Hillman reactions. The novel amidoamine...
    Resource Type:
    Dissertation
    Full Text:
    Activity. Abstract approved: Paul R. Blakemore Ambifunctional axially chiral 2,2

  • Total synthesis of sparteine alkaloids from a common tetraoxobispidine intermediate

    Creator:
    Melbardis, John
    Abstract:
    In previous work (Blakemore et al. Org. Lett. 2005, 7, 4721; Heterocycles 2006, 70, 609), successful elaborations of the lupine alkaloids (±)-α-isosparteine (dl-2) and (±)-β-isosparteine (dl-3) were realized from a common tetraoxobispidine precursor, 3,7-diallyl -2,4,6,8-tetraoxo-3,7-diazabicyclo[3.3.1]nonane (93). Herein, the tetraoxobispidine approach to lupine alkaloids was extended to a total synthesis of...
    Resource Type:
    Masters Thesis
    Full Text:
    Tetraoxobispidine Intermediate Abstract approved: Paul R. Blakemore In previous work (Blakemore et al

  • Investigation of Chain Extension Approaches for the Stereoselective Reagent-Controlled Synthesis of alpha-Heteroatom Substituted Alkyl Boronic Esters

    Creator:
    Barsamian, Adam L.
    Abstract:
    Two distinct strategies were explored for the enantioselective synthesis of α-heteroatom substituted alkyl boronic esters by stereoselective reagent-controlled homologation using transient chiral carbenoid reagents CHYMX (Y = heteroatom, X = nucleofuge, M = electrofuge). In the first case, a stereospecific reagent-controlled homologation (sStReCH) approach to α-alkoxyalkylboronates using α-metalated S,O- and...
    Resource Type:
    Dissertation
    Full Text:
    . Paul R. Blakemore Two distinct strategies were explored for the enantioselective synthesis of α

  • Stereospecific Synthesis of Stereotriad Motifs and Alkenes Using Enantioenriched sp³-Hybridized Carbenoids

    Creator:
    Xun, Sun
    Abstract:
    Enantioenriched sp³-hybridized carbenoid reagents CR1R2MX (X = nucleofuge, M = electrofuge) of different types were investigated for the synthesis of polysubstituted alkyl chains by iterative stereospecific reagent-controlled homologation (StReCH) and for the stereospecific connective synthesis of alkenes by eliminative cross-coupling. In the first part, putative enantioenriched α-chloroalkyllithiums (CHRLiCl) were employed...
    Resource Type:
    Dissertation
    Full Text:
    : ______________________________________________________ Paul R. Blakemore Enantioenriched sp3-hybridized carbenoid reagents CR1R2MX (X

  • Synthesis and catalytic applications of derivatives of 7,7'-dihydroxy-8,8'-biquinolyl (azaBINOL)

    Creator:
    Wang, Chao
    Abstract:
    The synthesis of axially chiral polyfunctional derivatives of 8,8'-biquinolyl was explored and the catalytic action of appropriate derivative types investigated in three separate processes: (1) the silylcyanation of carbonyl groups and imines, (2) alkylation of a glycine Schiff-base via phase transfer-catalysis, and (3) direct amide bond formation from simple amines...
    Resource Type:
    Dissertation
    Full Text:
    : Paul R. Blakemore The synthesis of axially chiral polyfunctional derivatives of 8,8´-biquinolyl