- Preparation method of (2, 6, 6-trimethyl-1-cyclohexenyl) acetaldehyde
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The invention provides a preparation method of (2, 6, 6-trimethyl-1-cyclohexenyl) acetaldehyde, which comprises the following steps: carrying out Grignard reaction on halogenated acetaldehyde acetal and magnesium powder to prepare a Grignard reagent, carrying out addition reaction on the obtained Grignard reagent and 2, 2, 6-trimethylcyclohexanone, and acidifying and deprotecting the obtained product to obtain (2, 6, 6-trimethyl-1-cyclohexenyl) acetaldehyde. The preparation method provided by the invention has the advantages of cheap and easily available raw materials, low cost, simple steps,safe and environment-friendly operation, easy realization, high reaction atom economy and selectivity, high yield and high purity, and is suitable for green industrial production. The obtained (2, 6,6-trimethyl-1-cyclohexenyl) acetaldehyde can be further used for preparing C14 aldehyde and vitamin A acetate.
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Paragraph 0076-0077
(2020/08/18)
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- Derivatives of erythromycylamine
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Three new groups of 9-N-substituted derivatives of erythromycylamine with superior oral activity against Gram-positive pathogens, new processes for preparing derivatives of erythromycylamine and aliphatic aldehydes by controlling the pH of the reaction and by catalytic hydrogenation, and pharmaceutical compositions and methods using the new compounds are provided.
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- Improved Synthesis of 2,6,6-Trimethyl-1-cyclohexene-1-acetaldehyde, a Key Intermediate for Drimanerelated Sesquiterpenes
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The titel compound is conveniently prepared in 65percent overall yield by a two step synthesis starting from the comercially available β-ionone.
- Jong, Johannes C. de,Wildeman, Jurjen,Leusen, Albert M. van,Feringa, Ben L.
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p. 589 - 596
(2007/10/02)
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- Enantiocontrolled synthesis of quaternary carbon centers via anionic oxy-cope rearrengement: An efficient synthesis of (+)-dihydromayurone
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(+)-Dihydromayurone (1) was enantioselectively synthesized from β-cyclocitral (7). The key step in the synthesis involved anionic oxy-Cope of allylic alcohol 6 to aldehyde 5. Efficient transfer of chirality from the secondary allylic alcohol center to the quaternary carbon center was observed vai chairlike transition state with the equatorial oxyanionic bond.
- Lee, Eun,Shin, In-Jae,Kim, Tae-Seong
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p. 260 - 264
(2007/10/02)
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- A New General Synthetic Approach to Diterpenes: Application to Syntheses of (+ -)-Taxodione and (+ -)-Royleanone.
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High-pressure Diels - Alder reactions of 1,3,3-trimethyl-2-vinyl-1-cyclohexenes 3a,b,i with substituted 1,4-benzoquinones afford, in good yield, highly functionalized tricyclic ring systems which are found in many classes of naturally occuring terpenes.Notably, the reactions of 3a are highly regio- and stereoselective.Efficient, formal syntheses of antitumor diterpenes (+ -)-taxodione and (+ -)-royleanone are reported, which demonstrate the practical application of this new strategy for the preparation of varied terpene systems.Of particular interest is that the high-pressure reactions are accelerated by mild Lewis acids and the regio- and stereoselectivity of these reactions is also improved under the combined high-pressure / Lewis acid conditions in comparison to the high-pressure conditions alone.Indeed, in the reaction of 3a with 2-methoxy-5-methyl-1,4-benzoquinone, ZnBr2 is required to effect the Diels-Alder reaction even at 12 kbar, and endo adduct 12c is formed stereoselectively in 90percent yield.In contrast, low-temperature Ti(IV)-catalyzed reactions of diene 3a with methoxy-substituted 1,4-benzoquinones at atmospheric pressure regioselectively produce dihydrobenzofurans 19 and 20, apparently via alkylation of the quinone Ti(IV) complex by the diene followed by the ring closure.
- Engler, Thomas A.,Sampath, Umashanker,Naganathan, Sriram,Velde, David Vander,Takusagawa, Fusao
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p. 5712 - 5727
(2007/10/02)
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- Ti/Cu AND Ti/Ag CATALYSTS FOR THE ISOMERISATION OF α-ACETYLENIC ALCOHOLS INTO α,β-ETHYLENIC CARBONYL DERIVATIVES
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New titanium and copper (or silver) based catalysts allow efficiently the isomerisation of α-acetylenic alcohols into α,β-ethylenic carbonyl deivatives.
- Chabardes, Pierre
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p. 6253 - 6256
(2007/10/02)
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- SYNTHESE TOTALE DU (+/-)POLIGODIAL, DE LA DRIMENINE ET DE COMPOSES APPARENTES A JONCTION DE CYCLE cis ET trans
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Isomerization by base under kinetic or thermodynamic control of the Diels-Alder adduct of 1,3,3-trimethyl-2-vinyl-1-cyclohexene with dimethyl acetylene dicarboxylate leads to two isomers which, after catalytic hydrogenation, give in high yield starting materials for synthesis of trans and cis drimanes.A short total synthesis of (+/-)-polygodial and (+/-)-drimenine from one of these isomers is desribed.
- Jalali-Naini, M.,Guillerm, D.,Lallemand, J-Y.
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p. 749 - 758
(2007/10/02)
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