Bridging the final gap in stereocontrolled Wittig reactions: methoxymethoxy-armed allylic phosphorus ylides affording conjugated dienes with high cis selectivity

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)]


Published in:
Chemistry - A European Journal, 6, 3, 420-426
Year:
2000
Keywords:
Note:
CAN 132:250900 23-2 Aliphatic Compounds Institut de Chimie organique de l'Universite Batiment de chimie (BCh),Lausanne-Dorigny,Switz. Journal 0947-6539 written in English. 97-96-1 (2-Ethylbutanal); 100-52-7 (Benzaldehyde); 105-07-7 (4-Cyanobenzaldehyde); 106-95-6 (Allyl bromide); 107-86-8; 111-71-7 (Heptanal); 123-11-5 (p-Anisaldehyde); 630-19-3 (Pivaldehyde); 870-63-3 (Prenyl bromide); 2548-87-0 ((E)-2-Octenal); 6728-26-3 ((E)-2-Hexenal); 18829-56-6 ((E)-2-Nonenal); 25152-84-5; 29576-14-5 ((E)-2-Butenyl bromide); 64935-37-1; 124629-80-7 Role: RCT (Reactant), RACT (Reactant or reagent) (stereoselective Wittig reaction of methoxymethoxy-substituted allylic phosphorus ylides); 128375-58-6P; 263008-19-1P; 263008-21-5P; 263008-23-7P Role: RCT (Reactant), SPN (Synthetic preparation), PREP (Preparation), RACT (Reactant or reagent) (stereoselective Wittig reaction of methoxymethoxy-substituted allylic phosphorus ylides); 31915-94-3P; 39491-55-9P; 39491-72-0P; 51447-08-6P; 66717-33-7P; 66717-34-8P; 69578-09-2P; 89510-84-9P; 107811-56-3P; 114444-92-7P; 153010-57-2P; 156050-04-3P; 169524-43-0P; 263008-27-1P; 263008-28-2P; 263008-29-3P; 263008-30-6P; 263008-31-7P; 263008-32-8P; 263008-33-9P; 263008-34-0P; 263008-35-1P; 263008-36-2P; 263008-37-3P; 263008-38-4P Role: SPN (Synthetic preparation), PREP (Preparation) (stereoselective Wittig reaction of methoxymethoxy-substituted allylic phosphorus ylides)
Laboratories:




 Record created 2006-03-03, last modified 2018-01-27


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