Allyl ionone

Allyl Cyclohexanepropionate, 452, 645 Allyl-3-cyclohexanepropionate, 452 4-Allyl-l,2-dimethoxy Benzene, 530 4-Allylguaiacol, 496 Allyl Heptanoate, 452, 605 Allyl Heptoate, 452 Allyl Hexanoate, 452, 645 Allyl Ionone, 452 Allyl a-Ionone, 452, 645 Allyl Isopentanoate, 452 Allyl Isothiocyanate, 452, 568, 681, (S3)64... 

Allylic alcohol. See Allyl alcohol Allyl ionone. See Allyl o-ionone Allyl a-ionone... 

Synonyms Allyl ionone CetoneV 1,6-Heptadien-3-one 1-(2,6,6-Trimethyl-2-cyclohexene-1 -yl)-1,6-heptadiene-3-one 1 -(2,6,6-Trimethyl-2-cyclohexenyl) hepta-1,6-dien-3-one Empirical C16H24O... 

Enone formation-aromatization has been used for the synthesis of 7-hydro-xyalkavinone (716)[456]. The isotlavone 717 was prepared by the elimina-tion[457]. The unsaturated 5-keto allyl esters 718 and 719, obtained in two steps from myreene. were subjected to enone formation. The reaction can be carried out even at room temperature using dinitriles such as adiponitrile (720) or 1,6-dicyanohexane as a solvent and a weak ligand to give the pseudo-ionone isomers 721 and 722 without giving an allylated product(458]. 

Reductive elimination of an allylic diol group. A new synthesis of vitamin A involves reduction of the allylic diol 1, prepared in several steps from JJ-ionone, with a low valent titanium formed from TiCl3 and LiAlH, in the ratio 2 1. Thus, the allylic diol group of 1 [either (E) or (Z)] is reduced to an (E,E)-1,3-diene group to form the silyl ether (2) of vitamin A.1 When the primary hydroxyl group is protected as an acetate, the reduction gives a mixture of (E)- and (Z)-2. 

Uric Acid (synthetic) Camphoric Acid Camphoronic Acid o-Esdragole from phenyl-allyl ether Ionone... 

Allylic CH bonds Aliphatic alkenes frequently undergo allylic substitution by oxidation of the double bond to a radical cation that undergoes deprotonation at the allylic position and subsequent oxidation of the resulting allyl radical to a cation, which finally combines with the nucleophiles from the electrolyte [21, 22]. The selectivity is mostly low. Regioselec-tive allylic substitution or dehydrogenation is, however, found in some cases with activated alkenes, for example, -ionone that reacts to (1) (Fig. 5) as a major product [23], menthone enolacetate that yields 90% (2) [24], and 3,7-dimethyl-6-octen-l-ol... 

Babler and Schlidt [86] described a route to a versatile C15 phosphonate, used for a stereoselective synthesis of all E retinoic acid and p-carotene. Base-catalyzed isomerization of the vinyl-phosphonate afforded the corresponding allyl-phosphonate as the sole product. Homer-Emmons olefination with ethyl 3-methyl-4-oxo-2-butenoate concluded the facile synthesis of all E ethyl retinoate. The C15 phosphonate was synthesized starting from the epoxide of P-ionone. Subsequent isomerization with MgBr2, afforded the C14 aldehyde in 93%... 

Amongst the monocyclic sesquiterpenes, the plant growth hormone (+)-abscisic acid 446 and a-humulene 451 are found which both can be synthesized by Wittig reactions. To synthesize (+)-abscisinic acid 446 D. L. Roberts et al. 239) converted a-ionone 444 into the allylic alcohol 445 by /-butyl chromate oxidation. 445 is reacted with ethoxycarbonylmethylene-triphenylphosphorane 238 and subsequently... 

This reaction based on the petrochemical crude material isobutylene makes the synthetic route to P-ionone (36) substantially shorter and cheaper, especially since the isomeric double bond proves to be advantageous in the subsequent reactions. In addition, i-methylheptenone (37 a) can be converted into methylheptenone (37) by noble metal-catalyzed isomerization. The reaction steps ethynylation (C2 addition), Carroll reaction (C3 addition), ethynylation and partial hydrogenation (C2 addition) lead from methylheptenone (37) via dehydrolinalool (42), pseudoionone (43) and p-ionone (36) to the C15 alcohol p-vinylionol (44). With triphenylphosphine (15), the desired C15 phosphonium salt (13), which is the second important synthetic building block for vitamin A and carotenoids16), is obtained directly from p-vinylionol, by allyl rearrangement. 

Allyl a-Ionone 647 Butadiene-Styrene 75/25 Rubber Citral... 

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