| 摘要 |
PCT No. PCT/EP97/06425 Sec. 371 Date Jan. 29, 1999 Sec. 102(e) Date Jan. 29, 1999 PCT Filed Nov. 18, 1997 PCT Pub. No. WO98/23570 PCT Pub. Date Jun. 4, 1998An improved process is described for preparing gamma , delta -unsaturated ke-tones, which are in demand as aroma substances and intermediates for vitamins and carotenoids, by reacting tertiary allyl alcohols and alkenyl alkyl ethers in the presence of acid catalysts at elevated temperature, which comprises carrying out the reaction in the presence of a phosphorus derivative of the formula IV where A and B are each a branched or unbranched alkyl or alkoxy having from 1 to 10 carbons, a substituted or unsubstituted aryl, cycloalkyl, aryloxy or cycloaryloxy; A can additionally be -H or -OH or A and B together are a substituted or unsubstituted tetramethylene or pentamethylene or substituted or unsubstituted phenyl-1,2-diol or 1,1'-binaphthyl-2,2'-diol.
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