- 173. β-Cleavage of Bis(homoallylic) Potassium Alkoxides. Preparation of 3-Hydroxypropyl and 4-Hydroxybutyl Propenyl Ketones from γ- and δ-Lactones. Synthesis of (+/-)-Rose Oxide
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Starting from γ- and δ-lactones 1-3, a two-step preparation of 3-hydroxypropyl and 4-hydroxybutyl propenyl ketones 10-18 is described, involving as the key step the β-cleavage of the bis(homoallylic) potassium alkoxides 4a-9a.This novel methodology is illustrated by a short synthesis of (+/-)-rose oxide (20).
- Snowden, Roger L.,Linder, Simon M.,Muller, Bernard L.,Schulte, Karl H.
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- Palladium catalyzed oxidation of biorenewable β-citronellol and geraniol for the synthesis of polyfunctionalized fragrances
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β-Citronellol and geraniol are bio-renewable compounds found in essential oils of various plants. Allylic oxidation of trisubstituted sterically highly encumbered carbon-carbon double bonds in their molecules with dioxygen can be efficiently catalyzed by the palladium acetate/p-benzoquinone combination under 5?10 atm of dioxygen pressure without the need for conventionally used metal co-catalysts. Both substrates gave allyl acetates in ca. 90% combined yield. The oxidation of geraniol proceeded with excellent site-selectivity involving only one of its two C[dbnd]C bonds. Geraniol gave both linear and branched allyl acetates in comparable yields, whereas the reaction of β-citronellol showed high regioselectivity for the corresponding branched product. Polyfunctionalized oxygenated terpenes produced from β-citronellol and geraniol are of a potential importance as ingredients for fragrance compositions.
- Venancio, Aldino N.,Menini, Luciano,Maronde, Daiane N.,Gusevskaya, Elena V.,Parreira, Luciana A.
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- PROCESS FOR THE PREPARATION OF CIS-ROSE OXIDE
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The present invention relates to a process for the preparation of a composition enriched in cis-2-(2-methylprop-1-enyl)-4-methyltetrahydropyran, comprising the catalytic hydrogenation of 2-(2-methylprop-1-enyl)-4-methylenetetrahydropyran in the presence of hydrogen and a heterogeneous catalyst comprising ruthenium.
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Paragraph 0085
(2013/05/09)
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- Aluminium triflate catalysed cyclisation of unsaturated alcohols: novel synthesis of rose oxide and analogues
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Aluminium trifluoromethanesulfonate was used as an efficient catalyst for the cycloisomerisation of several unsaturated alcohols into cyclic ethers such as rose oxide and some of its ether analogues.
- Coulombel, Lydie,Weiwer, Michel,Dunach, Elisabet
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experimental part
p. 5788 - 5795
(2010/03/03)
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- Comparative study of the vicinal functionalization of olefins with 2:1 bromide/bromate and iodide/iodate reagents
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A comparative evaluation was made on the syntheses of vicinal halohydrins, halo methyl ethers, and halo acetates from olefins using 2:1 Br-/BrO3- and I-/IO3- reagents. In many cases both reagents afforded products selectively in high yields. The highest halogen atom efficiencies attained were 97% and 93% for Br-/BrO3- and I-/IO3-, respectively. Of the two reagents, I-/IO3- was established to be the preferred reagent for vicinal functionalization of linear alkenes and also for halo acetate preparation. However, only Br-/BrO3- was effective for vicinal functionalization of trans-stilbene and chalcones.
- Agrawal, Manoj K.,Adimurthy, Subbarayappa,Ganguly, Bishwajit,Ghosh, Pushpito K.
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experimental part
p. 2791 - 2797
(2009/08/08)
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- Oxidation of alcohols to carbonyl compounds with CrO3· SiO2 in supercritical carbon dioxide
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Supercritical carbon dioxide (scCO2) is an effective reaction medium to perform the oxidation of primary and secondary aliphatic alcohols to the corresponding carbonyl compounds with chromium trioxide supported on silica. These reactions were performed by flowing a solution of the alcohol in scCO2 through a column containing the supported reagent and recovering the product by depressurization. This method avoids the use of organic solvents and the contamination of the products with chromium species.
- Gonzalez-Nunez, Maria Elena,Mello, Rossella,Olmos, Andrea,Accrete, Rafael,Asensio, Gregorio
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p. 1039 - 1042
(2007/10/03)
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- Photochemical and thermochemical solar syntheses using flat-bed solar collectors/solar reactors
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The invention relates to a method for carrying out photochemical and thermochemical solar syntheses by means of flat-bed solar light collectors without devices for focusing the sunlight. The method is particularly well suited for producing flavors, aromas and complex thereof. The flat-bed solar light collector is suitable especially for producing steroids and derivatives thereof. It can further be used for the photooxidation (photooxygenation) of terpene olefins and therefore for the synthesis of fragrants such as rose oxide, myrtenol and myrtenal which are of industrial interest. The solar collector is also suitable for photochemical addition reactions and rearrangements.
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Page column 6-7
(2008/06/13)
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- Process for producing a rose oxide
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An improved process for production of an isomer mixture of Z- and E-2-?2-Methyl-prop-1-en-1-yl-!-4-methyl-tetrahydropyran, more commonly known under the name cis- and trans-rose oxide, which as a rule contains at least 80% of the natural Z-isomers (cis-rose oxide) which are valuable in the perfume industry.
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- SYNTHESES OF TETRAHYDROPYRANS BY PPh3/CBr4 INDUCED CYCLIZATION OF ACETALS : APPLICATION TO A SYNTESIS OF ROSE OXIDE
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Substituted tetrahydropyrans are prepared in good yields by PPh3/CBr4 induced cyclization of acetals.The utility of this new procedure is illustrated by the synthesis of cis-2-(methyl-1 propenyl)-4 methyltetrahydropyran (rose oxide).
- Wagner, A.,Heitz, M.-P.,Mioskowski, C.
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p. 1971 - 1974
(2007/10/02)
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- Electrooxidative Cleavage of Carbon-Carbon Linkages. 1. Preparation of Acylic Oxoalkanoates from 2-Hydroxy- and 2-Acetoxy-1-cycloalkanones and Cycloalkanone Enol Acetates
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A methodology is described for the synthesis of acyclic oxoalkanoates 2 by electrooxidative cleavage of carbon-carbon linkages of 2-oxocycloalkan-1-ols 1 and cycloalkanone enol acetates 3.The electrolysis of 1 was carried out in a MeOH-LiClO4-(Pt) system at a constant applied voltage of 20 V by using a divided cell, giving 2 in 82-97 percent yields.On the other hand, 3 was electrolyzed in MeOH-AcOH (10:1)-LiClO4-(Pt) at 2-8 deg to give 2 in 72-79 percent yields.Electrolysis of 4-hydroxy-p-menth-8-ene afforded methyl (3R)-3,7-dimethyl-6-oxo-7-octenoate, a chiral synthetic block for the synthesis of (+)-rose oxide, in 84 percent yield.Similarly, the procedure could be applied to the preparation of methyl(+)-6-oxo-6,7-dihydrocitronellate from (+)-menthone enol acetate (74 percent) as well as 4-hydroxy-p-menthone (94 percent).Other lithium salts, i.e., LiBF4 and CF3CO2Li, can be used for the present purpose, but there are some difficulties in producing 2 with Et4NOTs and Et4NClO4.A plausible mechanism of the formation of 2 from 1 is also discussed.
- Torii, Sigeru,Inokuchi, Tsutomu,Oi, Ryu
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- FRAGMENTATION OF HOMOALLYLIC ALKOXIDES. SYNTHESIS OF PROPENYL and 2-METHYLPROPENYL KETONES FROM CARBOXYLIC ESTERS
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An efficient two-step synthesis of propenyl and 2-methylpropenyl ketones from carboxylic esters is described which uses as the key step the fragmentation of a potassium dihomoallylic alkoxide under mild thermolytic conditions.
- Snowden, Roger L.,Muller, Bernard L.,Schulte-Elte, Karl H.
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p. 335 - 338
(2007/10/02)
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- A ROSE OXIDE SYNTHESIS
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A four-step synthesis of rose oxide from crotonaldehyde by Grignard reaction, Claisen rearrangement, reduction, and cyclization, is reported.
- Ho, Tse-Lok,Din, Zia Din
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p. 1099 - 1102
(2007/10/02)
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- Reaction of Acetals with Grignard Reagents
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The reaction of dialkyl acetals derived from α,β-unsaturated aldehydes with Grignard reagents using TiCl4 in THF afforded the cross coupling products, allyl ethers, in high yields.The TiCl4-promoted reaction of alkyl 2,4-dichlorophenyl acetals, synthesized from 3,4-dihydro-2H-pyran or ethyl vinyl ether and 2,4-dichlorophenol, with Grignard reagents in THF at low temperature afforded the corresponding unsymmetrical ethers in high yields.When alkyl 2,4-dichlorophenyl acetals, synthesized from aromatic aldehyde or vinyl ethers and 2,4-dichlorophenol, were treated with Grignard reagents in benzene or toluene at room temperature in the absence of TiCl4, the cross coupling reaction took place and the corresponding ethers were isolated in good yields.
- Ishikawa, Hiroshi,Mukaiyama, Teruaki,Ikeda, Shigeru
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p. 776 - 780
(2007/10/02)
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- THE REACTION OF HYPOCHLOROUS ACID WITH OLEFINS. A CONVENIENT SYNTHESYS OF ALLYLIC CHLORIDES
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The reaction of HOCl with more highly substituted olefins in methylene chloride affords allylic chlorides in 60-80percent isolated yields.The utility of the reaction is illustrated with the synthesis of Rose oxide and α-monoterpenes.
- Hegde, Shridhar G.,Vogel, Martin K.,Saddler, John,Hrinyo, Tanya,Rockwell, Ned,et al.
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p. 441 - 444
(2007/10/02)
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- A NOVEL SYNTHESIS OF DL-MARMELOLACTONE AND DL-ROSE OXIDE BY ELECTROCHEMICAL OXYSELENENYLATION SEQUENCE
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One-step transformation of olefins 1 into allylic alcohols and ethers 3 has been accomplished by electrooxidative oxyselenylation-deselenenylation sequence.The electrochemical process furnished efficient syntheses of dl-marmelolactone 4 and dl-rose oxide 5.
- Torii, Sigeru,Uneyama, Kenji,Ono, Michio
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p. 2653 - 2654
(2007/10/02)
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