185254-91-5Relevant academic research and scientific papers
An approach to β-substituted γ-butyrolactones and its application to the synthesis of lignans
Isemori, Yuichi,Kobayashi, Yuichi
, p. 1941 - 1944 (2007/10/03)
Copper-catalyzed reaction of 4-cyclopentene-1,3-diol monoacetate with ArCH2MgCl afforded 4-arylmethyl-2-cyclopenten-1-ols regioselectively. Subsequent cleavage of the cyclopentene ring followed by functional group manipulation provided the key β-arylmethyl-γ-butyrolactones for the synthesis of lignans. In addition, synthesis of the rolipram lactone intermediate was accomplished.
A short synthesis of both enantiomers of enterolactone
Sibi, Mukund P.,Liu, Pingrong,Johnson, Michael D.
, p. 133 - 138 (2007/10/03)
A short and efficient synthesis of both enantiomers of enterolactone, a mammalian lignan, is described. The overall yield for the natural enterolactone, over seven steps, was 19% and for its enantiomer 27%.
Intramolecular regioselective insertion into unactivated prochiral carbon-hydrogen bonds with diazoacetates of primary alcohols catalyzed by chiral dirhodium(II) carboxamidates. Highly enantioselective total synthesis of natural lignan lactones
Bode,Doyle,Protopopova,Zhou
, p. 9146 - 9155 (2007/10/03)
Intramolecular insertion into unactivated prochiral C-H bonds of 3-aryl-1-propyl diazoacetates catalyzed by dirhodium(II) tetrakis[methyl 1-(3-phenyl propanoyl)imidazolidin-2-one-4(R or S)-carboxylate], Rh2(4R-MPPIM)4 or Rh2(4S-MPPIM)4, occurs in 91-96% ee and with virtually complete regiocontrol for the formation of β-benzyl-γ-butyrolactones. This methodology has been applied to the total synthesis of dibenzylbutyrolactone lignans (-)- and (+)-enterolactone, (-)- and (+)-hinokinin, and (+)-arctigenin from substituted cinnamic acids in 19-27% overall yields. Aryltetralin lignan (+)-isodeoxypodophyllotoxin was prepared from the reactant 3,4-(methylenedioxy)cinnamic acid in 36% yield overall, and the lactone precursor to (+)-isolauricerisinol was formed in 96.5% ee and 23% yield overall. Applications of the chiral Rh2(MPPIM)4 catalysts to fully aliphatic systems resulting in the formation of β-substituted-γ-butyrolactones with high regiocontrol and with 93-96% ee have demonstrated the generality of this methodology. A model that provides accurate predictions of β-substituted-γ-butyrolactone absolute configurations in these asymmetric metal carbene transformations is described.
