反应详情

To a mixture of one g. of 3,7-dimethyloct-6-en-1-al 1.5 g. of phosphonate (II; R' is ethyl, R1 is methyl, R6 is ethoxy, R12 is hydrogen) and 50 ml. of dimethylformamide, under nitrogen, is slowly added sodium ethoxide (prepared from 200 mg. of sodium and 12 ml. of ethanol). The mixture is allowed to stand at room temperature for one hour and then is worked up with ether. The ethereal extracts are dried, concentrated and then chromatographed on silica plates eluting with hexane/ether to yield ethyl 3,7,11-trimethyldodeca-2,4,10-trienoate which is predominantly trans at position C-2,3 and C-4,5.

1. additionTo a mixture of one g
2. customThe ethereal extracts are dried
3. concentrationconcentrated
4. customchromatographed on silica plates
5. washeluting with hexane/ether