Benzoic Acid → (1S,4aS,7aR)-7-(hydroxymethyl)-1-(methylcarbamoyloxy)-1,4a,5,7a-tetrahydrocyclopenta [c] pyrane-4-carboxylic acid methylester

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Reaction Steps

28.5 g of the above (1S, 4aS, 7aR )-7-(tert-butyldiemthylsilyloxymethyl)-1-(methylcarbamoyloxy)-1,4a,5,7a-tetrahydrocyclopenta [c] pyrane-4-carboxylic acid methylester were dissolved in tetrahydrofuran followed by addition of 35 g of benzoic acid. Next, 143 ml of tetra-n-butylammonium fluoride (1.0 M, tetrahydrofuran solution) were dropped in followed by stirring for 24 hours at room temperature. The reaction mixture was then extracted with ethyl acetate. After washing the organic phase with saturated aqueous sodium bicarbonate and brine, it was dried over magnesium sulfate. After distilling off the solvent under reduced pressure, the residue was purified by silica gel chromatography to obtain a colorless powder from the hexane-ether eluate in the form of (1S,4aS,7aR)-7-(hydroxy-methyl)-1-(methylcarbamoyloxy)-1,4a,5,7a-tetrahydrocyclopenta [c] pyrane-4-carboxylic acid methylester (20.0 g, yield: 98.4%). The physicochemical properties of this compound are described in Table 66, Compound No. I-315.

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