The generality of the [4+1] cyclopentene annulation was demonstrated by the total synthesis of (±)-pentalenene and its C-9 epimer which were prepared in a stereocontrolled manner in analogy with the synthesis of (±)-isocomene, (±)-hirsutene and (±)-pentalenic acid. The key features of this synthesis involved preparation of acid 161, its conversion to diazoketone 148, intramolecular cyclopropanation of this substance to vinylcyclopropane 163 and the vinylcyclopropane-cyclo pentene rearrangement of several derivatives of 195 to triquinanes 147, 146, 197, and 204. A detailed study of temperature, conformation, and electronic effects on the diradical scission of vinylcyclopropanes of type 195 was carried out under pyrolytic conditions. Conclusive results regarding conformational stability at C-9 were also attained and exploited in the context of stereocontrol at this center. As a result of this synthesis, several new methods of functional transformations emerged, such as the selective reduction of conjugated esters and a new method of preparation of enolethers from carboxylic acids. / Master of Science / incomplete_metadata
| Identifer | oai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/50070 |
| Date | January 1987 |
| Creators | Natchus, Michael George |
| Contributors | Chemistry |
| Publisher | Virginia Polytechnic Institute and State University |
| Source Sets | Virginia Tech Theses and Dissertation |
| Detected Language | English |
| Type | Thesis, Text |
| Format | v, 164 leaves, application/pdf, application/pdf |
| Rights | In Copyright, http://rightsstatements.org/vocab/InC/1.0/ |
| Relation | OCLC# 17604852 |
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