Source:http://linkedlifedata.com/resource/pubmed/id/11348126
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| Predicate | Object |
|---|---|
| rdf:type | |
| lifeskim:mentions | |
| pubmed:issue |
10
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| pubmed:dateCreated |
2001-5-11
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| pubmed:abstractText |
The photodeconjugation of the alpha-(4-trimethylsilyl-3-butynyl)-substituted senecio acid esters 7 was studied. Chiral alcohols ROH (9) were employed as auxiliaries to control the facial diastereoselectivity of the protonation step. The conversion of the four sugar alcohols diacetone-D-glucofuranose, diacetone-D-allofuranose, diacetone-D-gulofuranose, and diacetone-D-fructopyranose (9a-d) to the esters 7 was achieved in four steps employing 4-iodo-1-trimethylsilylbut-1-yne (3) as the alkylating agent (27-45% yield overall). Their photodeconjugation gave the corresponding beta,gamma-unsaturated (R)-esters 14a-d with moderate to excellent diastereomeric excess. The best results were achieved with diacetone-D-glucofuranose and diacetone-D-fructopyranose as the auxiliary (>95% de). To achieve the synthesis of the target compound 1 which has the (S)-configuration, the deconjugation was conducted with the diacetone-L-fructopyranose (ent-9d) derived ester ent-7d. L-Fructose (20) was prepared from L-sorbose (15) in a modified procedure that allowed for the isolation of intermediates. The 2-fold inversion of configuration worked nicely, and the fructofuranose 19 was obtained in 19% yield from L-sorbose. The conversion of L-fructose to the ester ent-7d was conducted in full analogy to the synthesis of its enantiomer 7d. Deconjugation of ester ent-7d yielded the product 2d (70% yield), which was reduced to the alcohol 1 (85% yield).
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| pubmed:language |
eng
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| pubmed:journal | |
| pubmed:status |
PubMed-not-MEDLINE
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| pubmed:month |
May
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| pubmed:issn |
0022-3263
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| pubmed:author | |
| pubmed:issnType |
Print
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| pubmed:day |
18
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| pubmed:volume |
66
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| pubmed:owner |
NLM
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| pubmed:authorsComplete |
Y
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| pubmed:pagination |
3427-34
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| pubmed:dateRevised |
2003-10-31
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| pubmed:year |
2001
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| pubmed:articleTitle |
Photochemical deconjugation of chiral 3-methyl-2-butenoates derived from carbohydrate-based alcohols: the influence of the sugar backbone on the facial diastereoselectivity.
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| pubmed:affiliation |
Lehrstuhl für Organische Chemie I, Technische Universität München, D-85747 Garching, Germany. thorsten.bach@ch.tum.de
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| pubmed:publicationType |
Journal Article
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