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The Synthesis of E,E,E-12-fluorofarnesol and E,Z-6-fluorofarnesol which are key intermediates for the study of biosynthesis of some sesquiterpenes, is decribed. E,E-Farnesyl acetate is treated with selenium dioxide to give E,E,E-12-hydroxy farnesyl acetate, which is transformed by DAST into E,E,E-12-fluorofarnesylacetate. The latter compound is hydrolyzed to E,E,E-12-fluorofarnesol. The Reformatsky reaction of 6-methyl-5-hepten-2-one with ethyl bromofluoroacetate affords ethyl 2-fluoro-3-hydroxy-3,7-dimethyl-6-octanoate. This ester is acetylated and eliminated to give ethyl(Z)-2-fluoro-3,7-dimethylocta-2,6-dienoate, which is transformed to allyl bromide via allylic alcohol. The allyl bromide is treated with dianion of methyl acetate to give -keto ester. The beta-keto ester is converted to diethyl phosphoryloxy compound. The conjugate addition of lithium dimethylcuprate to the latter compound gives fluoro ester, which is treated with DIBAL to afford E,Z-6-fluorofarnesol.
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