- Chemo-enzymatic enantio-convergent asymmetric synthesis of (R)-(+)-Marmin
-
Asymmetric biohydrolysis of trisubstituted terpenoid oxiranes (rac-1a-rac-3a) was accomplished by employing the epoxide hydrolase activity Rhodococcus and Streptomyces spp. Depending on the biocatalyst, the biohydrolysis proceeded in an enantio-convergent fashion and gave the corresponding vic-diols in up to 97% ee at conversions beyond the 50%-threshold. In order to avoid a depletion of the ee of product by further oxidative metabolism, bioconversions had to be conducted in an inert atmosphere with exclusion of molecular oxygen. The synthetic applicability of this method was demonstrated by the asymmetric total synthesis of the monoterpenoid coumarin (R)-(+)-Marmin in 95% ee.
- Edegger, Klaus,Mayer, Sandra F.,Steinreiber, Andreas,Faber, Kurt
-
p. 583 - 588
(2007/10/03)
-
- Two New 7-Geranyloxycoumarins from the Bark of Aegle Marmelos, an Indonesian Medicinal Plant
-
Two new 7-geranyloxycoumarins, chloromarmin and aeglin, were isolated from the bark of Aegle marmelos, and their structures were assigned to be 7-(7-chloro-6R-hydroxy-3,7-dimethyl-2-octenyloxy)coumarin (1) and 7-coumarin (2), respectively.
- Ohashi, Kazuyoshi,Watanabe, Hisashi,Ohi, Katsuhide,Arimoto, Hirokazu,Okumura, Yasuaki
-
p. 881 - 882
(2007/10/03)
-
- 7-HYDROXYCOUMARIN DERIVATIVES FROM THE JUICE OIL OF CITRUS HASSAKU
-
Three new 7-hydroxycoumarin derivatives have been isolated from the juice oil of whole fruits of Citrus hassaku, and their structures determined to be 7-(6R-hydroxy-3,7-dimethyl-2E,7-octadienyloxy)coumarin, (+/-)-7-hydroxy-6-linalylcoumarin and (R)-6-O-(4
- Masuda, Toshiya,Muroya, Yukari,Nakatani, Nobuji
-
p. 1363 - 1366
(2007/10/02)
-
- Microbiological transformations. 21. An expedient route to both enantiomers of marmin and epoxyauraptens via microbiological dihydroxylation of 7-geranyloxycoumarin
-
The expedient synthesis of either enantiomers of Marmin or Epoxyauraptens of high enantiomeric purity is described. This was achieved via a stereospecific dihydroxylation of the remote double bond of a geraniol derivative using the fungus Aspergillus niger.
- Zhang,Archelas,Meou,Furstoss
-
p. 247 - 250
(2007/10/02)
-
- SYNTHESES EN SERIE RACEMIQUE ET EN SERIE OPTIQUEMENT ACTIVE D'UNE FAMILLE DE DERIVES OXYGENES NATURELS DE L'OMBELLIFERONE. STRUCTURE SPATIALE DU (-)EPOXY-3',6' AURAPTENE.
-
3',6'-Epoxyaurapten and marmin were synthesized by a stereocontrolled way in racemic then in optically active forms from a chiral precursors.The synthetic strategy is of biomimetic type.The reaction sequence involved a Sharpless asymmetric epoxydation as the key-step to induce chirality.E nantiomeric conversion gave rise to the opposite unnatural serie.The structural dimensions of (-)3'6'-epoxyaurapten have been ascertained by means of X-ray cristallography.This route allows the preparation of related molecules.
- Aziz, Mostafa,Rouessac, Francis
-
p. 101 - 110
(2007/10/02)
-
- SYNTHESES DE LA (+)-MARMINE, DES (+)-EPOXY-6',7'- ET (-)-EPOXY-3',6'-AURAPTENES ET DES RACEMIQUES CORRESPONDANTS
-
The title compounds were prepared by short enantioselective syntheses from 7-geranyloxycoumarin.The key step to induce optical activity was a SHARPLESS epoxidation.Conditions of electrophilic cyclization were found to obtain good yields.This approach allowed also to obtain the glycol (+)-marmin.
- Aziz, Mostafa,Rouessac, Francis
-
p. 2579 - 2582
(2007/10/02)
-
