"Thermal rearrangement of 4-aryl-4-hydroxy-2-cyclobuten-1-ones and appl" by Kimberly Denise Fisher

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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