Oxygen-Directed Intramolecular Hydroboration
نویسندگان
چکیده
منابع مشابه
Oxygen-Directed Intramolecular Hydroboration
Metal-free homoallylic oxygen-directed intramolecular hydroboration is reported. Regioselectivities from 20:1 to 82:1 favoring the 1,3-dioxy-substituted products have been achieved using Me2S.BH3/TfOH followed by standard oxidative workup. Branching at the C5 position improves regioselectivity.
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Directed catalytic asymmetric hydroborations of 1,1-disubstituted alkenes afford γ-dioxaborato amides and esters in high enantiomeric purity (90-95% ee).
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Trienes 1 and 3 were obtained in five steps from ethyl 4-acetoxy-3-oxobutanoate and 6-iodo-3-methyl-1,3-hexadiene. Intramolecular Diels-Alder cyclization of 1 and 3 gave tricyclic lactones 2 and 4 as the major products, respectively. The key intermediate 4 was converted in two steps to trans-dihydroconfertifolin (5).
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ژورنال
عنوان ژورنال: Journal of the American Chemical Society
سال: 2008
ISSN: 0002-7863,1520-5126
DOI: 10.1021/ja800402g