cis-Disubstituted Cyclopropanesvia Asymmetric Catalytic Cyclopropenation: Synthesis of Cyclopropyl-dehydroamino Acids and of Dictyopterene C′
| Autor: | Jean-Claude Rossier, Paul Müller, Gérald Bernardinelli, Mary Moran, Christian Gränicher, Hassan Imogaı̈ |
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| Rok vydání: | 1998 |
| Předmět: |
chemistry.chemical_classification
Organic Chemistry Acetal Absolute configuration Dictyopterene Biochemistry Aldehyde Phosphonate Medicinal chemistry Catalysis Inorganic Chemistry chemistry.chemical_compound chemistry Drug Discovery Wittig reaction Stereoselectivity Physical and Theoretical Chemistry |
| Zdroj: | Helvetica Chimica Acta. 81:1754-1764 |
| ISSN: | 1522-2675 0018-019X |
| DOI: | 10.1002/(sici)1522-2675(19981007)81:10<1754::aid-hlca1754>3.0.co;2-v |
| Popis: | The cyclopropenation of diethoxypropyne (1) with methyl diazoacetate in the presence of [Rh₂{(2S)‐mepy}₄] (mepy=methyl 5‐oxopyrrolidine‐2‐carboxylate) proceeds with >95% ee. The resulting cyclopropenecarboxylate 2 underwent stereoselective hydrogenation to the cis‐cyclopropane 3. Hydrolysis of the acetal function of 3 liberated the formyl cyclopropenecarboxylate 4, which was transformed by Wittig reaction with the phosphonate 5 to afford dehydroamino acid 6 as a mixture of (Z)‐ and (E)‐isomers in various proportions. The (Z)‐isomer 6a was hydrolyzed, and the structure and the absolute configuration of the (Z)‐dicarboxylic acid 7a were established by X‐ray crystallography. The cis‐divinylcyclopropane 11 (ee>95%), in turn, was synthesized from 4 via Wittig reaction to afford 8, which was transformed to the aldehyde 10 and subjected to a second Wittig reaction. Thermolysis of 11 afforded (+)‐dictyopterene C′ (12) in quantitative yield. |
| Databáze: | OpenAIRE |
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