Theoretical studies of thermal syn elimination reactions

An ab initio molecular orbital study of two classes of thermal syn elimination reactions was undertaken in order to provide insight into the mechanism of these reactions. In general, thermal syn elimination reactions involve a one step process with a cyclic transition structure. The first class studied is termed 1,5 thermal eliminations and involve a six-membered ring transition structure. In particular, the reactants, transition structures and product geometries of the ethyl formate, phosphinate, and xanthate were optimized at the RHF/6-31G* level. In addition, MP2/6-31G* energies and RHF/6-31G* electrostatic potentials were calculated. Trends in calculated activation energies and electrostatic potentials agree with experimental results. It was determined that the C\sbα-O bond appears to be breaking first in the reaction. It was also found that the effect of polar substituents agree with experimental results. Electron withdrawing groups in the β position were found to change the order of bond breaking to C\sbβ-H bond dissociation while α electron donating groups significantly increase the C\sbα-O bond length in the transition structure.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Chemistry

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2011

Author dc:creator

• Erickson, Jon A.

Contributors dc:contributor

• Kahn, Scott D.

• Chemistry, Organic

Statement dc:rights

• Copyright 1992 Erickson, Jon A.

Language dc:language

eng

Identifier

AAI9236452
(UMI)AAI9236452

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/21747