Semester

Summer

Date of Graduation

2008

Document Type

Dissertation

Degree Type

PhD

College

Eberly College of Arts and Sciences

Department

Chemistry

Committee Chair

Bjorn C G Soderberg

Abstract

Cyclobutenediones have proven useful as starting materials for synthesis of highly functionalized biologically relevant molecules. The rearrangement of cyclobutendiones has a wide synthetic scope and can be utilized as a key step in the construction of quinones, benzo[o]isoxazoles, and 3-methylenoxoindoles having a variety of substitution patterns. Construction of these molecules involves thermolysis of 4-hydroxy-2,4-di-aryl-2-cyclobutenones derived from squaric acid ester. In each of the cases the mechanism proceeds through an initial ring opening of the cyclobutene to afford a ketene intermediate that subsequently undergoes a ring closure with various intermolecular nucleophiles. This methodology has been utilized in the construction of an ellipticine model system.

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