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

HRID 466269

Reaction equation

HRID 466269 reaction equation
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

Participants

8

Reactant 3

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

Product 1

HCID 13108355trans-6-Hydroxymethyl-2-methoxytetrahydropyran

Reagents, catalysts & solvents 4

HCID 313Hydrochloric AcidCatalystHCID 345198Adams' catalystCatalystHCID 887MethanolSolvent2×HCID 3283Diethyl EtherSolvent

Procedure

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.

Sources & evidence

ORD record
ord-015bccbdc4b14c03a46a0c18658a7ee9
Source dataset
uspto-grants-1992_10
Patent number
US05155240

Linked notes

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