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[摘要]：Di- and trisubstituted olefins are prepd. stereoselectively by reaction of Grignard reagents with diastereomeric enol phosphate mixts. in THF in the presence of Fe(acac)3 [and in some cases, either N-methylpyrrolidinone or 1,3-dimethylpropylene urea (DMPU)]; under the reaction conditions, (E)-enol phosphates react stereoselectively with Grignard reagents, forming (E)-alkenes stereoselectively and leaving the (Z)-enol phosphates unreacted. Under the reaction conditions, enol phosphates contg. chloride, nitrile, or carboxylic acid Me ester moieties react chemoselectively only at the enol phosphate moieties to give disubstituted alkenes, while attempted coupling of a bromo-substituted enol phosphate under similar conditions gives only elimination products. |
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