- Herstellung enantiomerenreiner Derivate von 3-Amino- und 3-Mercaptobuttersaeure durch SN2-Ringoeffnung des β-Lactons und eines 1,3-Dioxanons aus der 3-Hydroxybuttersaeure
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From (S)-4-methyloxetan-2-one (1), the β-butyrolactone readily available from the biopolyner (R)-polyhydroxybutyrate (PHB) and various C,N,O and S nucleophiles, the following compounds are prepared: (S)-2-hydroxy-4-octanone (3), (R)-3-aminobutanoic acid (7) and its benzyl derivative 5, (R)-3-azidobutanoic acid (6), (R)-3-mercaptobutanoic acid (10), (R)-3-(phenylthio)butanoic acid (8) and its sulfoxide 9.The (6R)-2,6-dimethyl-2-ethoxy-1,3-dioxan-4-one (4) from (R)-3-hydroxybutanoic acid undergoes SN2 ring opening with benzylamine to give the N-benzyl derivative (ent-5) of (S)-3-aminobutanoic acid in 30-40percent yield.
- Griesbeck, Axel,Seebach, Dieter
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- Preparation of stereoisomers of 3-sulfinylbutyric acid from (R)- and (S)-4-methyl-2-oxetanone
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The β-lactone ((S) and (R)-4-methyl-2-oxetanone, 1, ent-1), readily available from (R)- and (S)-3-hydroxybutyric acid, is opened by sodium hydrosulfide, sodium alkane- and arenethiolates, respectively, with inversion of configuration. The resulting 3-(alkylthio)-2f, 2g, and 3-(arylthio)butyric acids, 2b-2e, ent-2h-2k (Table 1), oxidized with hydrogen peroxide in acetone to give the corresponding 3-(alkylsulfinyl)- and 3-(arylsulfinyl)butyric acids as mixtures of diastereoisomers 3b-3k and 4b-4k. These are separated and the pure like and unlike diastereoisomers isolated and fully characterized (Table 4). Configurational assignments rest upon a crystal structure analysis and comparison of properties in the two series.
- Breitschuh,Seebach
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