Stereoselective synthesis of highly substituted bicyclic gamma-lactones using homoaldol addition of 1-(1-cycloalkenyl)methyl carbamates

Stereoselective addition of aldehydes 4 to metallated 1-(1-cycloalkenyl)methyl NN-diisopropylcarbamates 1 gave cyclic homoaldol adducts 6. By applying the (-)-sparteine method, enantiomerically enriched products were obtained. These were oxidatively cyclized to diastereomerically pure gamma-lactones...

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Bibliographic Details
Published inSynthesis (Stuttgart) no. 14; pp. 2303 - 2316
Main Authors Ozlugedik, M, Kristensen, J, Reuber, J, Frohlich, R, Hoppe, D
Format Journal Article
LanguageEnglish
Published STUTTGART Thieme Medical Publishers 01.10.2004
Subjects
Chemistry
Chemistry, Organic
Physical Sciences
Science & Technology
1-alkenyl carbamates
DEPROTONATION
asymmetric synthesis
HOMOENOLATE REAGENTS
bicyclic lactones
homoaldol addition
LITHIATION
(-)-sparteine
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Summary:Stereoselective addition of aldehydes 4 to metallated 1-(1-cycloalkenyl)methyl NN-diisopropylcarbamates 1 gave cyclic homoaldol adducts 6. By applying the (-)-sparteine method, enantiomerically enriched products were obtained. These were oxidatively cyclized to diastereomerically pure gamma-lactones 8 via the gamma-lactol ethers 7. After deprotonation of gamma-lactones 8 with lithium hexamethyldisilazide, a further substitution was achieved. By trapping the lactone enolates 11 with beta-naphthylmethyl bromide, single diastereomers of gamma-lactones 12 were produced.
ISSN:0039-7881
1437-210X
DOI:10.1055/s-2004-831170