I. GEOMETRIC EFFECTS IN SULFUR LONE-PAIR INTERACTIONS. II. SYNTHETIC USES OF SULFOXIMINES, SULFOXIDES AND HEMITHIOKETALS WITH STEREOCHEMICAL CONTROL.

Persistent Link:
http://hdl.handle.net/10150/184042
Title:
I. GEOMETRIC EFFECTS IN SULFUR LONE-PAIR INTERACTIONS. II. SYNTHETIC USES OF SULFOXIMINES, SULFOXIDES AND HEMITHIOKETALS WITH STEREOCHEMICAL CONTROL.
Author:
ANDRUSKI, STEPHEN WALTER.
Issue Date:
1987
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
An X-ray crystal analysis of l,8-Bis(methylthio)naphthalene (1.1) revealed that the molecule has a geometry in which the naphthalene ring is twisted to place the 1,8- substituents symmetrically above and below the naphthalene plane. The methyl groups are rotated out of the naphthalene plane. X-ray crystal analysis of Naphtho [1, 8-b, c] -1, 5- dithiocin (1.2) showed that naphthalene ring is twisted as in 1.1, however the disposition of the sulfurs above and below the plane is unsymmetrical. The aliphatic portion of the molecule is in a chair-like conformation. Comparison of these two structures indicates that the bond asymmetry across the naphthalene ring is due largely to bond stretching to relieve steric overcrowding. MNDO calculations on 1.1 and 1.2 give HOMO's which are predominantly naphthalene in character. Our MNDO eigenvalues for 1.1 and naphtho[l,8-d,e]-l,3-dithiin (2.1) correlate well with their PES ionization potentials. We predict an ionization potential of -7.60-7.76eV for 1.2. Reduction of the ethylene hemithioketal of norcamphor is shown to proceed with heterolysis of the carbon-oxygen bond and hydride attack on the resulting thionium ion occurring from the sterically less hindered exo face of the norbornane moiety. The stereochemistry of the resulting substituted norbornanes (3.4 and 3.5) is proved to be endo. In the reduction of N-phthalimido sulfoximines to sulfoxides with hydrazine in ethanol, a species is formed which gives reduction of certain unsaturated compounds. The reducing species is shown not to be diimide. Formation of 1,1-diazene is a possible explanation for the experimental results. The cycloaddition of (±)-S-2'-thienyl-S-vinyl-Nphthalimidosulfoximine ((±)-5.1g) with cyclopentadiene proceeds in good yield, however asymmetric induction in the resulting adducts is negligible. This strongly indicates that steric factors are controlling the asymmetric induction in this cycloaddition. (±)-Thiochromone-l-oxide (±)-5.8) and (±)-N-phthalimido-l-imino-4-thiochromone-l-oxide (±)- 5.6) are shown to undergo Diels-Alder reactions with cyclopentadiene in good yields giving only endo products with good diastereoselectivity. The diastereoselectivity of the reaction of (±)-5.8 with cyclopentadiene is shown to increase when the reaction is run at -78° with AlCl₃ as a catalyst. These results can be interpreted on the basis of approach of the diene on the less hindered face of the more reactive conformer.
Type:
text; Dissertation-Reproduction (electronic)
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Chemistry; Graduate College
Degree Grantor:
University of Arizona

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleI. GEOMETRIC EFFECTS IN SULFUR LONE-PAIR INTERACTIONS. II. SYNTHETIC USES OF SULFOXIMINES, SULFOXIDES AND HEMITHIOKETALS WITH STEREOCHEMICAL CONTROL.en_US
dc.creatorANDRUSKI, STEPHEN WALTER.en_US
dc.contributor.authorANDRUSKI, STEPHEN WALTER.en_US
dc.date.issued1987en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAn X-ray crystal analysis of l,8-Bis(methylthio)naphthalene (1.1) revealed that the molecule has a geometry in which the naphthalene ring is twisted to place the 1,8- substituents symmetrically above and below the naphthalene plane. The methyl groups are rotated out of the naphthalene plane. X-ray crystal analysis of Naphtho [1, 8-b, c] -1, 5- dithiocin (1.2) showed that naphthalene ring is twisted as in 1.1, however the disposition of the sulfurs above and below the plane is unsymmetrical. The aliphatic portion of the molecule is in a chair-like conformation. Comparison of these two structures indicates that the bond asymmetry across the naphthalene ring is due largely to bond stretching to relieve steric overcrowding. MNDO calculations on 1.1 and 1.2 give HOMO's which are predominantly naphthalene in character. Our MNDO eigenvalues for 1.1 and naphtho[l,8-d,e]-l,3-dithiin (2.1) correlate well with their PES ionization potentials. We predict an ionization potential of -7.60-7.76eV for 1.2. Reduction of the ethylene hemithioketal of norcamphor is shown to proceed with heterolysis of the carbon-oxygen bond and hydride attack on the resulting thionium ion occurring from the sterically less hindered exo face of the norbornane moiety. The stereochemistry of the resulting substituted norbornanes (3.4 and 3.5) is proved to be endo. In the reduction of N-phthalimido sulfoximines to sulfoxides with hydrazine in ethanol, a species is formed which gives reduction of certain unsaturated compounds. The reducing species is shown not to be diimide. Formation of 1,1-diazene is a possible explanation for the experimental results. The cycloaddition of (±)-S-2'-thienyl-S-vinyl-Nphthalimidosulfoximine ((±)-5.1g) with cyclopentadiene proceeds in good yield, however asymmetric induction in the resulting adducts is negligible. This strongly indicates that steric factors are controlling the asymmetric induction in this cycloaddition. (±)-Thiochromone-l-oxide (±)-5.8) and (±)-N-phthalimido-l-imino-4-thiochromone-l-oxide (±)- 5.6) are shown to undergo Diels-Alder reactions with cyclopentadiene in good yields giving only endo products with good diastereoselectivity. The diastereoselectivity of the reaction of (±)-5.8 with cyclopentadiene is shown to increase when the reaction is run at -78° with AlCl₃ as a catalyst. These results can be interpreted on the basis of approach of the diene on the less hindered face of the more reactive conformer.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineChemistryen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.identifier.proquest8712858en_US
All Items in UA Campus Repository are protected by copyright, with all rights reserved, unless otherwise indicated.