Functionalized Chiral Vinyl Aminosulfoxonium Salts: Asymmetric Synthesis and Application to the Synthesis of Enantiopure Unsaturated Prolines, β,γ-Dehydro Amino Acids, and Cyclopentanoid Keto Aminosulfoxonium Ylides
| Autor: | Gadamsetti S. Babu, Hans-Joachim Gais, Gerhard Raabe, Markus Günter, Shashi Kant Tiwari, Andreas Lindenmaier, Vijaya Bhaskara Reddy Iska, Stefan Koep, Leleti Rajender Reddy, Franz Köhler |
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| Rok vydání: | 2006 |
| Předmět: |
chemistry.chemical_classification
organic chemicals Enantioselective synthesis General Chemistry Highly selective Biochemistry Catalysis Amino acid chemistry.chemical_compound Colloid and Surface Chemistry Enantiopure drug chemistry Intramolecular force Organic chemistry Organic synthesis Isomerization |
| Zdroj: | Journal of the American Chemical Society. 128:7360-7373 |
| ISSN: | 1520-5126 0002-7863 |
| Popis: | Methylation of the enantiopure functionalized vinyl sulfoximines 5a-e and 14a-d followed by a F- ion or DBU-mediated isomerization of the vinyl aminosulfoxonium salts 7a-e and 15a-d, respectively, gave the allyl aminosulfoxonium salts 10a-e and 17a-d, respectively. A concomitant intramolecular substitution of the aminosulfoxonium group of 10a-e and 17a-d by the amino group afforded the unsaturated prolines 8a-e and 18a-d, respectively. The starting vinyl sulfoximines are accessible through a highly selective and stereo-complementary aminoalkylation of the corresponding sulfonimidoyl-substituted mono- and bis(allyl)titanium complexes with the imino ester 4. The vinyl aminosulfoxonium salts 34, 7a-d, and E-15c experienced upon treatment with the Cl- ion a migratory substitution with formation of the delta-chloro-beta,gamma-dehydro amino acids 36, E/Z-37a-d, and 38, respectively. A migratory substitution of the hydroxy-substituted vinyl aminosulfoxonium salts 46a and 46b furnished the delta-chloro allyl alcohols E/Z-48a and E-48b, respectively. A facile one-pot conversion of the vinyl sulfoximines 31b, 5c and 45a to the allyl chlorides 36, E/Z-37c and E/Z-48a, respectively, was achieved upon treatment with a chloroformiate. A tandem cyclization of the vinyl aminosulfoxonium salts 7b, Al-7b and 57 with LiN(H)tBu yielded the cyclopentanoid keto aminosulfoxonium ylides 54, Al-54, 59, 60 and 61, respectively. The structure of the tricyclic keto aminosulfoxonium ylide Al-54 has been determined by X-ray crystal structure analysis. Ab initio calculations and a NBO analysis of the tricyclic keto aminosulfoxonium ylide XXIII show a polar structure stabilized by electrostatic interactions between the ylidic C atom and both the carbonyl C atom and the S atom. |
| Databáze: | OpenAIRE |
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