Bridging the Final Gap in Stereocontrolled Wittig Reactions: Methoxymethoxy-Armed Allylic Phosphorus Ylides Affording Conjugated Dienes with Highcis Selectivity
| Autor: | Qian Wang, Manfred Schlosser, Mirella El Khoury |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Phosphine oxide
Steric effects Allylic rearrangement Organic Chemistry Stereochemistry (stereoselective Wittig reaction of methoxymethoxy-substituted allylic phosphorus ylides) Alkadienes Role: SPN (Synthetic preparation) General Chemistry stereoselective Wittig reaction methoxymethoxy allylic phosphorus ylide alkadiene stereoselective prepn Medicinal chemistry Catalysis Crotyl chemistry.chemical_compound chemistry Sodium amide Wittig reaction Butyllithium PREP (Preparation) (stereoselective prepn. of alkadienes by Wittig reaction of methoxymethoxy-substi Organic chemistry Phosphonium |
| Zdroj: | Chemistry - A European Journal. 6:420-426 |
| ISSN: | 1521-3765 0947-6539 |
| Popis: | After treatment with an appropriate base (butyllithium or sodium amide), 2-alkenyltris(2-methoxymethoxyphenyl)phosphonium salts carrying an allyl, crotyl, or prenyl (3-methyl-2-butenyl) side chain condense with satd. or unsatd. aldehydes to give conjugated dienes with Z/E ratios ranging from 90:10 to > 99:1 and averaging 96:4. Owing to steric congestion, yields are only moderate (on av. 41%; extremes 10-79%). The nonvolatile tris(2-methoxymethoxyphenyl)phosphine oxide byproduct can be readily isolated and reduced to recover the phosphane starting material, or it may be hydrolyzed to the water-sol. tris(2-hydroxyphenyl)phosphine oxide. [on SciFinder (R)] |
| Databáze: | OpenAIRE |
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