Index Catalog // ScholarsArchive@OSU

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

Precursor-directed Biosynthesis and Total Synthesis of Aniline-containing Natural Products from the Endophytic Fungus Chalara sp. 6661

Creator:: Khoshbakht, Mahsa
Abstract:: Chalaniline A, an unusual xanthone-like aminofulvene with modest cytotoxicity, and chalaniline B [1-anilino-2,8-dihydroxy-3-(hydroxymethyl)xanthone], an antibacterial aminoxanthone, were previously isolated by Loesgen and coworkers from vorinostat-treated Chalara sp. 6661. Of note, the anilino moiety found within both chalaniline structures originates from biotransformation of the HDAC inhibitor vorinostat (SAHA, suberanilohydroxamic acid) by...
Resource Type:: Dissertation

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

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

Scaffold reactivity and large scale Synthesis of organocatalyzed Yamada-Otani Condensation product and investigation of the synthesis and properties of axially chiral 8,8'-biquinolyls and 8-(naphtha-1-yl)quinolines

Creator:: Banerjee, Somdev
Abstract:: In Part I, (4S,5R)-4,5-dimethyl-4-phenylcyclohex-2-enone (19a) was prepared in 73% yield with high enantio- and diastereo-selectivity (er > 98:2, dr > 20:1) on a multigram scale by a Yamada-Otani condensation between (E)-pent-3-en-2-one and 2-phenylpropanal catalyzed by a sulfonimide derivative of (S)-proline (18, HuaCat®). Synthetically useful transformations of the cyclohexenone product 19a...
Resource Type:: Dissertation

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

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

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

Chain extension of boronic esters with stereo- and regio-defined lithiated oxiranes

Creator:: Alwedi, Embarek
Abstract:: The stereospecific reagent-controlled homologation (StReCH) of boronic esters with putative lithiooxiranes generated in situ from appropriate precursors via sulfoxide-lithium exchange, tin-lithium exchange, and direct lithiation is described with an emphasis on the first lithiation technique which allows for the regio- and stereo-specific generation of all types of lithiooxirane isomer. Transient...
Resource Type:: Dissertation

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

ScholarsArchive@OSU

Stereocontrolled Synthesis of Allenes by Eliminative Cross-Coupling of Carbenoids

Precursor-directed Biosynthesis and Total Synthesis of Aniline-containing Natural Products from the Endophytic Fungus Chalara sp. 6661

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

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

Scaffold reactivity and large scale Synthesis of organocatalyzed Yamada-Otani Condensation product and investigation of the synthesis and properties of axially chiral 8,8'-biquinolyls and 8-(naphtha-1-yl)quinolines

Development of Methods for Stereoselective Carbon-Carbon Bond Formation

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

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

Chain extension of boronic esters with stereo- and regio-defined lithiated oxiranes

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

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