Isoprene epoxide

Ketone carbonyl group (-C(O)-) KET Isoprene epoxide product EPOX... 

Reaction with isoprene epoxide. Alkyllithium reagents undergo 1,4-addition to isoprene epoxide to give predominately (Z)-allylic alcohols, particularly in the presence of a base (equation I). The reaction was used to prepare a-santalol (I) from n-bromotricyclene. 

Terpenoid Synthesis from Isoprene.—Co-oxidation of thiophenol and isoprene with oxygen yields the synthons (9) and (10) in useful yields and the isoprene epoxide (11) is a useful hemiterpenoid synthon with carbanions. ... 

Iron(III)sulfate, 223-224 Isatin, 331 Isatoic acid, 331 Isoatlantolactone, 263, 264 Isobutenyl acetate, 153 Isobutyronitrile, 110 Isocyanates, 14-15 Isoflavones, 410 Isopavine, 217 Isopenams, 325 Isophorone, 197, 198 Isopinocampheylborane, 224 Isoprene epoxide, 4 Isopropenyl phenyl sulfone, 316 Isopropenyltriphenylphosphonium bromide, 225... 

Isoprene epoxidized on the vinyl group (l,2-epoxy-3-methyl-3-butene, 14) would also be an attractive synthon for monoterpenoids if it were more readily accessible. Among the possible preparative methods (Scheme 2), acid-catalyzed isomerization of 2,3-epoxy-l-halo-3-methylbutanes (epoxidized prenyl halides) and dehydrohalogenation of the resulting isomers seemed the best route until chlorination of prenyl acetate (15, R = OAc) with hypochlorous acid was published. Dehydration of the mixture of products gave a maximum of the chloroacetate 16, which yielded the epoxide 14 with sodium hydroxide in methanol. ... 

ALLYLIC REARRANGEMENT Isoprene epoxide. Sulfuric acid. tt-ALLYLPALLADIUM chloride COMPLEXES Bis(benzonitrile)paUadium(II) chloride. 

Isopentenylhydroquinone, 397, 398 Isopentyl nitrite, 48 Isophorone, 287 oxide, 282, 283, 394 Isoprene dimers, 4-5 Isoprene epoxide, 79 isoprenoid quinones, 250 Isoprenylation, 397-398 N-Isopropylideneanilines, 3 Isopropylidenecarbene. 358 Isup ropy I idenecy do propanes, 358... 

For the synthesis of sarcinaxanthin (441) in racemic form a biomimetic, acid-promoted prenylation reaction has been described. The key step was the alkylation-cyclization of geranyl acetate (214) with the isoprene epoxide 215 to give, in a mixture, 216 with the desired 2,6-cw-stereochemistry. The primary alcohol group was transformed to the corresponding mesylate which was dehydrated and subsequent hydrolysis gave 217. Conversion of 217 into the sulphone 218 was achieved by preparation of the corresponding mesylate, followed by... 

The selected example below is that of the synthesis of a butterfly pheromone in which palladium is involved in two C-C bond formation steps. From isoprene epoxide, the action of palladium leads to the opening of the epoxide, and the attaek of the first carbanion is not stereoselective. This is not inconvenient, however. 

Isoprene epoxide and (l,5-cyclooctadiene-RhCl)2 in anhydrous CCI4 heated 50 hrs. at 70° under 150 atm. CO in a stainless-steel autoclave -> 5-methyl-3,6-dihydro-pyran-2-one. Y 75%. F. e., also 5,6-dihydro isomers with Fe- or Co-catalysts, s. R. Aumann and H. Ring, Ang. Ch. 89, 47 (1977). 

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