| 摘要 |
PURPOSE:To obtain the titled compound, by using a dihydropyran derivative capable of being synthesized from L-lactic acid as a raw material, protecting carbon at 3-position with bromine, oxidizing a double bond to give a diol, regenerating the dihydropyran ring with a specific metal, and oxidizing it. CONSTITUTION:Carbon atom at 3-position of a dihydropyran derivative shown by the formula I (R is lower alkyl) is protected with bromine by the use of N-bromosuccinimide, then the double bond is oxidized with osmium tetroxide to give a diol derivative. The compound is treated with a metal (e.g., zinc, iron, nickel, especially preferably zinc) having ionization tendency smaller than zinc and larger than hydrogen to regenerate the dihydropyran ring, which is oxidized with lead tetraacetate, to give (-)-elenophosphoric ester shown by the formula II. EFFECT:An elenophosphoric ester can be synthesized stereoselectively by a simple synthetic procedure. USE:An antiviral agent. A raw mateiral for ajmalicine useful as an antihypertensive, tranquilizer, etc.
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