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For example, he treats the O-allyl alpha-d-glucoside with mercuric trifluoroacetate. This results in addition of mercury to the middle carbon atom of allyl alcohol and a second glucose hydroxyl group to the end carbon atom of the double bond. Treatment of that intermediate with sodium borohydride transforms the end carbon atom to a methyl group. Treatment of the resulting sugar derivative with boron trifluoride etherate and hydrogen peroxide frees up (R)-propylene glycol.
He admits that the use of mercury is objectionable. Also, the conditions for releasing the product alcohol are severe. This is because the product is attached to the glucose auxiliary in two places, which ironically is the source of the high asymmetric induction
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