Investigation of the steric and/or electronic effects associated with the (1,5)-sigmatropic rearrangement of 1-substituted-2,3,4,5-tetraphenyl- 2,4-cyclopentadien-1-ols

A series of eight l-substituted-2,3,4,5-tetraphenyl-2,4-cyclopentadien-l-ols were efficiently synthesized by the addition of the appropriate organometallic reagent to tetracyclone. It was determined that the steric and electronic nature of the migrating groups played a predictable role in the [l,5]-sigmatropic rearrangement of these compounds. Electron donating groups increased the rate of migration whereas electron withdrawing substituents were responsible for slowing the migration. Likewise, smaller groups accelerated the rate while bulky groups deterred the migration. Consequently, the experimental evidence supports the originally proposed charge separated transition state. The Michael addition of potassium cyanide to tetracyclone afforded upon protonation a diastereomeric mixture of the cis (kinetic product) and the trans (thermodynamic product) 4-cyano-2,3,4,5-tetraphenyl-2-cyclopenten-l-ones. Finally an efficient synthesis of 2,3,4,5-tetraphenyl-2(1H)-pyridinone (90%) resulted from the acid promoted addition of sodium azide to tetracyclone. The presence of an intermediate bicyclic triazoline eliminated the Schmitt mechanism as a viable reaction pathway.

Name thesis:degree_name

Ph. D.

Level thesis:degree_level

doctoral

Discipline thesis:degree_discipline

Chemistry

Department dc:contributor.department

Chemistry

Grantor dc:publisher

Virginia Polytechnic Institute and State University

Year dc:date.issued

1986

Author dc:creator

• Eagan, Robert Lee

Chair dc:contributor.committeechair

• Ogliaruso, Michael A.

Committee members dc:contributor.committeemember

• Bell, Harold M.
• Kingston, David G. I.
• Mason, John G.
• Wightman, James P.

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en_US

Handle dc:identifier.uri

http://hdl.handle.net/10919/74730

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/74730