3,4-dihydro-2H-pyran → trans-6-Hydroxymethyl-2-methoxytetrahydropyran

HRID 466269

Reaktionsgleichung

Reaktionsgleichung von HRID 466269
O1C=CCCC1.[CH3:7][O:8][CH:9]1[CH:14]=[CH:13][CH2:12][CH:11]([C:15](OC)=[O:16])[O:10]1.[H-].[Al+3].[Li+].[H-].[H-].[H-]>CO.Cl.C(OCC)C.[Pt](=O)=O>[OH:16][CH2:15][C@@H:11]1[O:10][C@@H:9]([O:8][CH3:7])[CH2:14][CH2:13][CH2:12]1

Komponenten

8

Edukt 3

HCID 80803,4-dihydro-2H-pyranHCID 5572662H-Pyran-2-carboxylic acid, 3,6-dihydro-6-methoxy-, methyl esterHCID 21226445Aluminium lithium hydride

Produkt 1

HCID 13108355trans-6-Hydroxymethyl-2-methoxytetrahydropyran

Reagenzien, Katalysatoren, Lösungsmittel 4

HCID 313Hydrochloric AcidKatalysatorHCID 345198Adams' catalystKatalysatorHCID 887MethanolLösungsmittel2×HCID 3283Diethyl EtherLösungsmittel

Versuchsvorschrift

The absolute configuration for the product was determined by first isomerizing the dihydropyran derivative product in methanol by use of hydrochloric acid as a catalyst so that the product had a trans-isomer content of 95%, subsequently converting the ester into an alcohol in diethyl ether by use of lithium aluminum hydride, and then hydrogenating the double bonds by using platinum dioxide in methanol to give trans-6-hydroxymethyl-2-methoxytetrahydropyran, followed by optical rotation measurement. As a result, the optical rotation [α]20 of the above compound was found to be -119.9° (c=1.07, solvent: benzene). This found value was compared with the optical rotation [α]20 of +129.7° (c=4.3, solvent: benzene) for (2S,6S)-6-hydroxymethyl-2-methoxy-3,4,5,6-tetrahydropyran as described in J. Jurczak et al., J. Chem. Soc., Chem. Commun., pp. 540-542 (1983). Based on the comparison, the trans-isomer and cis-isomer were judged to be a (2R,6R)-isomer and a (2S,6R)-isomer, respectively.

Quellen und Nachweise

ORD-Eintrag
ord-015bccbdc4b14c03a46a0c18658a7ee9
Quelldatensatz
uspto-grants-1992_10
Patentnummer
US05155240

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