Synthesis of (−)-Tetracycline
| Autor: | Andrew G. Myers, Dionicio Siegel, Mark G. Charest |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Autoxidation
Chemistry Stereoisomerism Sulfoxide General Chemistry Benzoic Acid Tetracycline Biochemistry Medicinal chemistry Catalysis Cycloaddition Anti-Bacterial Agents Palladium black chemistry.chemical_compound Colloid and Surface Chemistry Yield (chemistry) Trifluoroacetic acid Organic chemistry Enone Benzoic acid |
| Zdroj: | Journal of the American Chemical Society. 127:8292-8293 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | We describe a convergent, enantioselective synthesis of (-)-tetracycline (1) from benzoic acid (17 steps, 1.1% yield). Benzoic acid was transformed into the AB precursor 2 in 10 steps (11% yield), as previously described, and the latter compound was activated toward Diels-Alder cycloaddition by the introduction of an alpha-phenylthio group (two steps, 66% yield). Heating of the resulting alpha-(phenylthio)enone (3) with the triethylsilyloxybenzocyclobutene derivative 4 at 85 degrees C gave the endo-Diels Alder adduct 5 in 64% yield. Deprotection and oxidation of the latter intermediate gave the 2-(phenylthio)-1,3-diketone 7, which was oxidized with m-chloroperoxybenzoic acid in the presence of trifluoroacetic acid. The sulfoxide intermediate(s) formed eliminated upon warming to 35 degrees C to give the anyhydrotetracycline derivative 8. Intermediate 8 underwent spontaneous autoxidation at 23 degrees C to form the hydroperoxide keto-9 stereoselectively. Without isolation, hydrogenolysis of 9 in the presence of palladium black gave (-)-tetracycline (42% yield from 7), indistinguishable from an authentic sample. |
| Databáze: | OpenAIRE |
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