Ionone epoxide

Preparation of optically active P-ionone epoxide by a solid state kinetic resolution in the presence of the chiral host 10a is also possible. When a mixture of 10a, P-ionone (66) and m-chloroperbenzoic acid (MCPBA) is ground by mortar and pestle in the solid state, (+)-67 of 88% ee was obtained.29 Mechanism of the kinetic resolution is shown below. Of course, all processes proceed in the solid state. Firstly, oxidation of 66 with MCPBA gives rac-P-ionone epoxide (67). Secondly, enantioselective inclusion of (+)-67 with 10a occurs. Thirdly, uncomplexed (-)-67 is oxidized to give the Baeyer- Villiger oxidation product (-)-68 of 72% ee. This is the first example of the resolution by an enantioselective inclusion complexation in the solid state. 

Toda, F., Mori, K., Matsuura, Y., and Akai, H. (1990) Solid State Kinetic Resolution of b-Ionone Epoxide and Dialkyl Sulphoxides in the Presence of Optically Active Host Compounds. The First Enantioselective Host-Guest Inclusion Complexation in the Solid State,... 

Several papers have described the synthesis of epoxyretinoids. The 5,6-epoxides of fmns-retinal (88) and its (9Z)-, (IIZ)-, and (13Z)-isomers were prepared by direct epoxidation of retinal with w-chloroperbenzoic acid. The 7,8-epoxides (89) of retinal, retinol, and retinoic acid and its methyl esters were synthesized from the jS-ionone epoxide (90). The exceedingly labile methyl 13,14-epoxy-13,14-dihydroretinoate (91) was made by addition of the epoxyaldehyde (92) to the phosphorane (93). Chromogen 574 , a product of the epoxidation of retinol first described in 1945, has now been identified as the... 

Compound (185) underwent rearrangement in the presence of acetic acid to give (186), and in the presence of methanolic potassium hydroxide gave 4-hy-droxyretinoic acid (187) (Rosenberger, 1982) (see Section V). The 7,8-ep-oxy-7,8-dihydroretinoids (498), (499), (500), and (501) were synthesized by coupling the (3-ionone epoxide (494) to the anion of the all-trans C7 phosphonate (495). The epoxy esters (496) and (497) were obtained after purification by HPLC. 

Oxidoalcohols from oxidoketones. 13 g. v -ionone epoxide in methanol treated with 0.5 mole NaBH4 until spectroscopic control shows the reduction... 

Epoxidation of aldehydes and ketones is the most profound utility of the Corey-Chaykovsky reaction. As noted in section 1.1.1, for an a,P-unsaturated carbonyl compound, 1 adds preferentially to the olefin to provide the cyclopropane derivative. On the other hand, the more reactive 2 generally undergoes the methylene transfer to the carbonyl, giving rise to the corresponding epoxide. For instance, treatment of P-ionone (26) with 2, derived from trimethylsulfonium chloride and NaOH in the presence of a phase-transfer catalyst Et4BnNCl, gave rise to vinyl epoxide 27 exclusively. ... 

As described in equation 78, the relatively electron-rich ring double bond of a- or fi-ionone was regioselectively epoxidized, whereas the electron-deficient double bond was not oxidized at all. This result also supports the radical rather than the anionic character of 52. 

Arylidene-,6-ionones, triplet oxygen cycloaddition, 199, 201 Aryl phosphites, ozone adducts, 732 Aryl-substituted olefins, selenide-catalyzed epoxidation, 384-5 Ascaridole... 

Various mono- or di-olefins were oxidized regioselectively to their epoxides in high yield with the 2-nitrobenzenesulfonylperoxy intermediate 51 generated in situ from 2-nitrobenzenesulfonyl chloride and KO2 at —35 °C in CH3CN (equation 78)226. Thus /J-ionone was oxidized using 51 to the corresponding mono epoxide product in high yield (83%). That the electron-deficient double bonds remain intact under the reaction conditions shows the electrophilic character of 51. 

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%... 

A simple epoxide related to ionone has been isolated from amber oil by Ruzicka and Seidel, and the structure (Xll) tentatively assigned to it.1413 Vitamin A epoxide (XIII) is believed to coexist with vitamh... 

Thus, oxygen attack at the terminal 5,6-double bond position, followed by the formation of a peroxy epoxide and cleavage of the C-C and 0-0 bonds, resulted in 5,6-epoxy-B-ionone, while rearrangement of the 5,6-epoxy derivative, followed by reduction and oxidation, resulted in the formation of dihydroactinidiolide. Furthermore, a peroxy derivative was formed and cleaved to form 8-ionone, which then led to the formation of dihydroactinidiolide as a secondary oxidation product. 

Baeyer-Villiger oxidation. This peracid converts p-ionone (3) selectively into the product of Baeyer-Villiger oxidation (5). Oxidation of 3 with monoper-phthalic acid or m-chloroperbenzoic acid yields the epoxide (4) of 3 or of the... 

Ionone-5,6-epoxide (199) undergoes acid-catalysed ring contraction and enlargement, concurrently, by [1,2] alkyl shifts, to give the isomeric cyclopentane derivative (200) and the cycloheptafuran derivative (201).71 /3-Ionone (132) can be hydrogenated selectively with P-1 nickel catalyst to give dihydro-/3-ionone (202).72... 

Kamer and Stununger provided further support- for this premise -when they atiowod that tx-ionone undergoes epoxidation only at tin-f xbonyl-oonjugated double bond (Eq. 60). 

In a-ionone, peroxybenzoic acid and peroxyphthalic acid epoxidize solely the endocyclic double bond to give 3,4-epoxy-a-ionone in 96.5 and 66% yields, respectively [299]. Alkaline hydrogen peroxide, on the other hand, epoxidizes only the double bond conjugated with carbonyl to give a 28-31% yield of a-ionone-ot, p -epoxide [332] (equation 440). 

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