- A stereospecific synthesis of vicinal amino alcohols by aminolysis of vinylepoxides
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Several vinylepoxides have been prepared and subjected to a TsOH·H2O-catalyzed aminolysis reaction to afford the corresponding amino alcohols in good yields. The nucleophilic addition is stereospecific and proceeds with high regioselectivity at
- Lindstroem, Ulf M.,Franckowiak, Remi,Pinault, Nathalie,Somfai, Peter
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- Synthesis of vinyl 1,2-diketones
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A new route is outlined for preparation of vinyl 1,2-diketones via a three-step sequence. First, allylic alcohols are photooxidized by 1O2 to hydroperoxides, which are reduced to vinyl 1,2-diols. These vinyl 1,2-diols are oxidized to vinyl 1,2-diketones with oxoammonium salts, which are prepared in situ from organic nitroxyl radicals. The new route is short, avoids the use of protecting groups, and is generally applicable to obtain aliphatic or aromatic vinyl 1,2-diketones.
- Habel, Lothar W.,De Keersmaecker, Sigrid,Wahlen, Joos,Jacobs, Pierre A.,De Vos, Dirk E.
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p. 4057 - 4059
(2007/10/03)
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- 3-Bromopropenyl esters in organic synthesis: Indium- and zinc-mediated entries to alk-1-ene-3,4-diols
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Metallic indium and zinc readily add to 3-bromopropenyl acetate (5) and benzoate (6) either in THF or in water, affording the corresponding 3-acyloxyallyl organometallic compounds. Nucleophilic addition to aldehydes opens a route to alk-l-ene-3,4-diols 2 in good to excellent yields. Two synthetic protocols were developed, the former involving indium in THF under Grignard conditions and the latter involving zinc in aqueous ammonium chloride under Barbier conditions. The diastereo-selectivity, under all the conditions examined, mainly depends on the nature of the carbonyl compound; conjugated aldehydes afford syn adducts 2, while unconjugated aldehydes display the opposite anti stereopreference.
- Lombardo, Marco,Morganti, Stefano,Trombini, Claudio
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p. 997 - 1006
(2007/10/03)
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