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Your search keyword '"Timothy D. W. Claridge"' showing total 7 results
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7 results on '"Timothy D. W. Claridge"'

1. Biomimetic Synthesis of the Crispatene Core

Author

and Timothy D. W. Claridge, John E. Moses, Robert M. Adlington, Rodolfo Marquez, Barbara Odell, and Jack E. Baldwin

Subjects
Core (optical fiber), Crispatene, Chemistry, Biomimetic synthesis, Yield (chemistry), Organic Chemistry, One-Step, Nanotechnology, Physical and Theoretical Chemistry, Biochemistry
Abstract

The biomimetic synthesis of the crispatene core is reported. The core framework was efficiently generated from an easily synthesized all (E)-tetraene precursor in one step, in good yield.

Published
2003
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2. 'Pure by NMR'?

Author

Edward D. Savory, Angela J. Russell, Timothy D. W. Claridge, Andrew D. Smith, Stephen G. Davies, Paul M. Roberts, and Mario E. C. Polywka

Subjects
Chemistry, Component (thermodynamics), Carbon-13 NMR satellite, Organic Chemistry, Proton NMR, Analytical chemistry, Resonance, Physical and Theoretical Chemistry, Biochemistry
Abstract

Integration of a (13)C-(1)H satellite peak of a given (12)C-(1)H parent resonance within a quantitative (1)H NMR spectrum and comparison to the minor component represents a simple protocol for the accurate determination of diastereoisomeric ratios of up to 1000:1 (i.e., 99.8% de).

Published
2008

3. Highly (E)-selective Wadsworth-Emmons reactions promoted by methylmagnesium bromide

Author

Andrew D. Smith, Timothy D. W. Claridge, Rebecca L. Nicholson, James A. Lee, Stephen G. Davies, Paul M. Roberts, Steven M. Toms, and Angela J. Russell

Subjects
chemistry.chemical_classification, chemistry.chemical_compound, chemistry, Bromide, Organic Chemistry, Organic chemistry, Physical and Theoretical Chemistry, Biochemistry, Medicinal chemistry, Alkyl
Abstract

An experimentally simple protocol for the very highly (E)-selective Wadsworth-Emmons reaction [(E):(Z) selectivities in excess of 180:1 in some cases] of a range of straight-chain and branched aliphatic, substituted aromatic, and base-sensitive aldehydes via reaction with an alkyl diethylphosphonoacetate and MeMgBr is reported.

Published
2008

4. A two-directional approach to enantiopure 1,4-difluoro-cyclohexenes: synthesis of difluorinated cyclitol analogues

Author

Barbara Odell, Timothy D. W. Claridge, Sophie Purser, Véronique Gouverneur, and Peter R. Moore

Subjects
chemistry.chemical_classification, Allylic rearrangement, Double bond, Stereochemistry, Cyclitol, Cyclohexenes, Organic Chemistry, Electrophilic fluorination, Stereoisomerism, Fluorine, Metathesis, Biochemistry, chemistry.chemical_compound, Enantiopure drug, chemistry, Dihydroxylation, Organic chemistry, Physical and Theoretical Chemistry, Cyclitols
Abstract

Enantiopure 1,4-difluoro-cyclohexenes were prepared from readily available acetonide-protected (3 S,4 S)-hexa-1,5-diene-3,4-diol. In a two-directional mode, a double cross-metathesis reaction using allyltrimethylsilane as the olefinic partner, followed by electrophilic fluorination, afforded diastereomeric acetonide-protected 3,6-difluoro-octa-1,7-diene-4,5-diols. These dienes were found to be suitable substrates for ring-closing metathesis, delivering cyclohexenes featuring fluorine atoms on the two allylic positions flanking the double bond. Upon dihydroxylation, novel difluorinated cyclitol analogues were formed.

Published
2008

5. “Pure by NMR”?

Author

Timothy D. W. Claridge, Stephen G. Davies, Mario E. C. Polywka, Paul M. Roberts, Angela J. Russell, Edward D. Savory, and Andrew D. Smith

Subjects
*NUCLEAR magnetic resonance, *RESONANCE, *QUANTITATIVE chemical analysis, *SPECTRUM analysis, *DIASTEREOISOMERS, *STEREOCHEMISTRY
Abstract

Integration of a 13C−1H satellite peak of a given 12C−1H parent resonance within a quantitative 1H NMR spectrum and comparison to the minor component represents a simple protocol for the accurate determination of diastereoisomeric ratios of up to 1000:1 (i.e., 99.8% de). [ABSTRACT FROM AUTHOR]

Published
2008
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6. Highly (E)-Selective Wadsworth−Emmons Reactions Promoted by Methylmagnesium Bromide.

Author

Timothy D. W. Claridge, Stephen G. Davies, James A. Lee, Rebecca L. Nicholson, Paul M. Roberts, Angela J. Russell, Andrew D. Smith, and Steven M. Toms

Subjects
*CHEMICAL reactions, *MAGNESIUM compounds, *BROMIDES, *ALDEHYDES, *ACETATES, *AROMATIC compounds
Abstract

An experimentally simple protocol for the very highly (E)-selective Wadsworth−Emmons reaction [(E):(Z) selectivities in excess of 180:1 in some cases] of a range of straight-chain and branched aliphatic, substituted aromatic, and base-sensitive aldehydes via reaction with an alkyl diethylphosphonoacetate and MeMgBr is reported. [ABSTRACT FROM AUTHOR]

Published
2008
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7. A Two-Directional Approach to Enantiopure 1,4-Difluoro-cyclohexenes: Synthesis of Difluorinated Cyclitol Analogues.

Author

Sophie Purser, Timothy D. W. Claridge, Barbara Odell, Peter R. Moore, and Véronique Gouverneur

Subjects
*PHONEMICS, *PHONOLOGY, *PHONETICS, *GRAPHEMICS, *PHONICS
Abstract

Enantiopure 1,4-difluoro-cyclohexenes were prepared from readily available acetonide-protected (3 S,4 S)-hexa-1,5-diene-3,4-diol. In a two-directional mode, a double cross-metathesis reaction using allyltrimethylsilane as the olefinic partner, followed by electrophilic fluorination, afforded diastereomeric acetonide-protected 3,6-difluoro-octa-1,7-diene-4,5-diols. These dienes were found to be suitable substrates for ring-closing metathesis, delivering cyclohexenes featuring fluorine atoms on the two allylic positions flanking the double bond. Upon dihydroxylation, novel difluorinated cyclitol analogues were formed. [ABSTRACT FROM AUTHOR]

Published
2008
Full Text
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