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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Stereocontrolled synthesis with phenylthio migration

Aggarwal, V. K. January 1986 (has links)
No description available.
42

Mechanistic studies of diastereoselective cyclopropanations of homochiral ene-ketals and synthesis and resolution of diastereomeric alpha-hydroxycycloalkanone ketals.

Hemperly, Susan Barbara. January 1989 (has links)
A series of homochiral ene ketals were prepared and subjected to the Simmons-Smith cyclopropanation. A mechanistic model was formulated to explain the observed diastereoselectivity seen for the common ring systems. Diastereoselectivity is thought to result from preferential chelation of the Simmons-Smith reagent at the least sterically hindered lone pair of electrons on the dioxolane oxygen proximal to the alkene. The role of dioxolane oxygen was inferred from studies with a hydrocarbon model system. The effect of cyclohexene ring conformation on the diastereoselectivity was examined for conformationally restricted ene ketal systems. Reagent chelation by the pseudoequatorial dioxolane oxygen atom was shown to be favored. This preference can either antagonize or reinforce diastereoselectivity due to steric hindrance of the dioxolane oxygen atoms from dissymmetric placement of the appendages on the dioxolane ring. A general method for the chromatographic resolution of diastereomeric α-hydroxycycloalkanone ketals derived from 1,4-di-O-benzyl-L-threitol is reported. Separability is thought to result from differences in intramolecular hydrogen bonding for the two diastereomeric forms.
43

Complexities and dynamics of the enantioselective site in heterogeneous catalysis : tartaric acid and methylacetoacetate on Cu(110)

Lorenzo, Maria Ortega January 1999 (has links)
No description available.
44

Mechanistic investigation into coenzyme B←1←2 enzymes

Ciceri, Daniele January 2000 (has links)
No description available.
45

Stereocontrol in organic chemistry : Some new approaches

Russel, A. T. January 1987 (has links)
No description available.
46

Preparation of η³-allylmolybdenum complexes using cis-Mo(CO)₄(THF)₂ : application to the synthesis of methyl pseudomonate C

Uppal, Sukhjinder Singh January 2003 (has links)
No description available.
47

Synthetic and metal binding studies of cyclic peptides

Freeman, David J. January 1999 (has links)
No description available.
48

Crystallographic studies of 6-phosphogluconate dehydrogenase

Pelly, K. C. M. January 1987 (has links)
No description available.
49

The Stereochemistry of the Cycloaddition of Unsymmetrical Phenyl Ketenes to Cyclopentadiene

Parry, Fred H. 05 1900 (has links)
This dissertation is a study involving the synthesis and chemistry of arylhaloketenes and cyclopentadiene cycloadducts, and a study of the cycloadduct isomer distribution was begun.
50

The Stereochemistry and Mechanism of Alkylhaloketene-Olefin Cycloadditions

Roe, Robert, 1934- 06 1900 (has links)
The objectives of this research problem was to employ alkylhaloketene-olefin isomer distributions to aid in understanding the stereochemistry and mechanism of alkylhaloketene-olefin cycloadditions.

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