A highly efficient approach to 2,3-disubstituted indoles has been presented. The indole precursors, isonitriles, were used as powerful geminal radical donors/acceptors. The novel isonitrile-alkyne free radical cascade has been efficiently mediated by tin and sulfur. In the case of sulfur, interesting 2,3-dithioindoles were formed. This new class of compounds has exhibited great promise as versatile indole intermediates. In particular, nucleophilic additions at C-10 of the 2,10-dithioindoles were achieved using carbon, sulfur and amine nucleophiles. The versatility of 2,10-dithioindoles was further demonstrated using rhodium-mediated sulfur ylide chemistry. We achieved an intramolecular sulfur ylide reaction which led to a gramine-type addition product 270. Furthermore, sulfur ylides were formed intermolecularly and rearranged to give highly substituted indoles. In studies aimed at the synthesis of the spirotryprostatins, our 2,10-dithioindoles were used in the synthesis of both a simple C-3 spiro-oxindole compound 249 and a diketopiperazine-containing indole derivative 256. This demonstrated the exciting potential of our indole-forming reaction and elaboration methodologies in natural product synthesis.
| Identifer | oai:union.ndltd.org:arizona.edu/oai:arizona.openrepository.com:10150/290368 |
| Date | January 2001 |
| Creators | Kennedy, Abigail Rose |
| Contributors | Rainier, Jon D. |
| Publisher | The University of Arizona. |
| Source Sets | University of Arizona |
| Language | en_US |
| Detected Language | English |
| Type | text, Dissertation-Reproduction (electronic) |
| Rights | Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. |
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