- 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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- Sequential Ru-Pd catalysis: A two-catalyst one-pot protocol for the synthesis of N- and O-heterocycles
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An atom economic, selective, and highly practical two-metal one-pot synthesis of heterocycles has been developed that efficiently affords enantio- and diastereopure N- and O-heterocyclic products. Furthermore, use of a chiral catalyst in the two-metal procedure allows formation of all possible diastereomers, even those that are traditionally difficult to access via cyclization routes due to thermodynamics. Interestingly, the nature of the enantiodiscriminating event differs between the use of amine versus alcohol nucleophiles. The method also affords heterocyclic products that are synthetically useful intermediates. Through the Z-vinylsilane a variety of stereodefined trisubstituted olefin products can be accessed including several all-carbon motifs. Finally, the utility of these heterocyclic products in total synthesis is demonstrated through concise syntheses of a kainoid intermediate, a constituent of oil of rose, and the ring B portion of bryostatin, a potent chemotherapeutic.
- Trost, Barry M.,Machacek, Michelle R.,Faulk, Brian D.
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p. 6745 - 6754
(2007/10/03)
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- Synthesis and odor of optically active rose oxide
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Stereoselective synthesis of optically active rose oxide (1) by KHSO4 and Pd-BINAP-catalyzed cyclization of (3R)- and (3S)-3,7-dimethyl-6,7-octadien-1-ol (5) is described. One-pot synthesis of the (3R)- and (3S)-allenyl alcohol 5 from (3R)- and (3S)-citronellol (2) (98% ee) is also described. Furthermore, the odor properties of the four diastereomers of 1 are reported.
- Yamamoto, Takeshi,Matsuda, Hiroyuki,Utsumi, Yasuhide,Hagiwara, Toshimitsu,Kanisawa, Tsuneyoshi
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p. 9077 - 9080
(2007/10/03)
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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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- Photochemical rearrangement of 2-phenylthio-1,3-cyclohexanediols to deoxysugars. Application to a stereospecific synthesis of (+)-cis-rose oxide
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The present paper reports the stereospecific synthesis of (+)-cis-rose oxide, the unnatural isomer of the fragrant oil isolated from Bulgarian roses and Bourbon geraniums. The synthesis serves to illustrate the potential of a new photochemical rearrangement of carbocycles to deoxysugars reported earlier.
- Gravel, Denis,Bordeleau, Josee
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p. 8035 - 8038
(2007/10/03)
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- On the Mode of Baker's Yeast Reduction of Methyl Substituted Arylalkyl Gamma and Delta Keto Acids. Synthesis of Cis-(+)-Rose Oxide.
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Baker's yeast reduction of methyl substituted γ- and δ-keto acids 1-6 proceeds in a mode depending upon subtle substrate modifications; it affords γ-lactones of modest ee and de values and highly functionalized, enantiomerically pure δ-lactones, such as 13 from which cis-(+)-rose oxide 23a has been prepared.
- Fronza, Giovanni,Fuganti, Claudio,Grasselli, Piero,Terreni, Marco
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p. 7363 - 7372
(2007/10/02)
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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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- 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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p. 1879 - 1885
(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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