17187-75-6Relevant academic research and scientific papers
Efficient Asymmetric Syntheses of Naturally Occurring Lignan Lactones Using Catalytic Asymmetric Hydrogenation as a Key Reaction
Morimoto, Toshiaki,Chiba, Mitsuo,Achiwa, Kazuo
, p. 1793 - 1806 (2007/10/02)
Optically pure (R)-arylmethylsuccinic acid mono-methyl esters were obtained efficiently by using the catalytic asymmetric hydrogenation of arylidenesuccinic acid monoesters with a rhodium(I) complex of a chiral bisphosphine, (4S,5S)-MOD-DIOP.Asymmetric total syntheses of some naturally occurring lignans, (+)-collinusin, (-)-deoxypodophyllotoxin, and (+)-neoisostegane, were achieved via several steps from (R)-γ-butyrolactones as key intermediates obtained by reduction of (R)-arylmethylsuccinic acid mono methyl-esters.
Asymmetric total synthesis of (-)-deoxypodophyllotoxin
Morimoto,Chiba,Achiwa
, p. 261 - 264 (2007/10/02)
An efficient total synthesis of (-)-deoxpophyllotoxin has been achieved by employing the asymmetric hydrogenation of α-piperonylidene-succinic acid half ester with a rhodium(I) complex of (S,S)-MOD-DIOP as a key step.
Highly Enantiospecific Synthesis of 4-Alkyl and 4,5-Dialkyl Substituted 4,5-Dihydrofuran-2(3H)-ones from Optically Active (E)- and (Z)-Alk-1-enyl p-Tolyl Sulphoxides: Application to the Synthesis of Lignan Lactones
Kosugi, Hiroshi,Tagami, Katsuya,Takahashi, Akira,Kanna, Hiroshi,Uda, Hisashi
, p. 935 - 943 (2007/10/02)
Stereochemically and optically pure 2-substituted ethylenic p-tolyl sulphoxides (R)-E-(4) and (R)-Z-(4) undergo readily and stereospecifically an additive Pummerer rearrangement reaction with dichloroketene to give trans- and cis-β-alkyl-α,α-dichloro-γ-p-tolylthio-γ-butyrolactone derivatives (5), respectively.Sequential reductive dechlorination and desulphurization lead to (-)-(S)-, from trans-(5), and (+)-(R)-β-alkyl-γ-butirolactones (7), from cis-(5), with a high optical purity, respectively.Reaction of the intermediate tolylthio derivatives (6) with allyltributylstannane gives β-alkyl-γ-allyl-γ-butyrolactones (15) and (16).These sequential reactions can be successfully applied to the synthesis of (+)-(R)-β-piperonylbutyrolactone (20), the key intermediate for the synthesis of antileukemic lignan lactones, in high chemical and optical yields.Acylation of compound (20) with 3,4,5-trimethoxybenzoyl chloride furnishes (+)-podorhizon (21).
LIGNANES.10. PREPARATION DES (R)-(+) ET (S)-(-)-β-PIPERONYL ET β-VERATRYL-γ-BUTYROLACTONES ET LEUR UTILISATION DANS LA SYNTHESE TOTALE DE LIGNANES OPTIQUEMENT ACTIFS
Brown, Eric,Daugan, Alain
, p. 141 - 154 (2007/10/02)
A simple and efficient route leading to optically active β-benzyl-γ-butyrolactones is described.Thus, the methyl (R,S)-α-benzylhemisuccinate resulting from a Stobbe condensation with an appropriate aromatic aldehyde, followed by catalytic hydrogenation of the intermediate α-benzylidene hemisuccinic ester, was resolved by means of a chiral base (ephedrine or α-methyl benzylamine).Reduction of each enantiomer, using calcium borohydride, then led to the corresponding optically active β-benzyl-γ-butyrolactone.In this way, the following two lactones were obtained in both (R)-(+) and (S)-(-) enantiomeric forms, β-piperonyl- and β-veratryl-γ-butyrolactones 1 and 2 respectively.These lactones were used as key-intermediates for the syntheses of 17 optically active lignans and lignoids, such as (-)-dimethylmatairesinol (-)-23, (-)-kusunokinin (-)-26 and (+)-dimethylisolariciresinol (+)-35.
SYNTHESES TOTALES ET ETUDES DE LIGNANES BIOLOGIQUEMENT ACTIFS-II. APPLICATION DE L'α-HYDROXYALKYLATION DE β-BENZYL χ-BUTYROLACTONE A LA CREATION DES SQUELETTES PHENYL TETRALINE ET BISBENZOCYCLOOCTADIENES. SYNTHESE TOTALE DU (+/-) PODORHIZOL, DE LA (+/-) P
Robin, Jean-Pierre,Dhal, Robert,Brown, Eric
, p. 3667 - 3671 (2007/10/02)
The use of lithium hexamethyldisilylamide (LHDS) in α-hydroxyalkylation of β-(3,4-methylenedioxybenzyl)-χ-butyrolactone gives high yields of (+/-) podorhizol and (+/-) epi-podorhizol as a 1:1 diastereoisomer mixture.Cyclisation of both alcohols using trif
