- Unified approach to the sesquiterpenoids, lauranes and cyclolauranes: Total synthesis of (±)-isolaurene
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A general approach to the total synthesis of sesquiterpene, isolaurene (1a) and cyclolaurene (2a) is featured from commercially available 3-methyl cyclopenten-2-one. The strategy includes a Stork-Danheiser sequence concomitant with a Ni(II)-catalyzed conj
- Niyogi,Khatua, Arindam,Bisai, Vishnumaya
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- Mono- and bicyclic cyclopentenes by rearrangement of 1-methylcyclobutylmethanols: synthesis of (±)-cuparene and formal syntheses of (±)-laurene and (±)-herbertene
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Addition of 1-methylcyclobutylmagnesium chloride (3) to acyclic (4d, e) and cyclic ketones (4a-c) yields 1-methylcyclobutylmethanols (5a-e), which may be rearranged to mono(11-14) and bicyclic cyclopentenes (6-10), respectively. Compounds 11, 12, and 13 are known precursors of (±)-laurene (15), (±)-cuparene (16), and (±)-herbertene (17), respectively. The cyclopentene 11 has been used in a two step synthesis of (±)cuparene (16).
- Mandelt, Klaus,Fitjer, Lutz
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p. 1523 - 1526
(2007/10/03)
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- SYNTHESIS OF AROMATIC SESQUITERPENES, (+/-)-CUPARENE AND (+/-)-LAURENE BY MEANS OF AN INTRAMOLECULAR CARBENOID DISPLACEMENT (ICD) REACTION
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The synthesis of (+/-)-cuparene and (+/-)-laurene was accomplished by means of an intramolecular carbenoid displacement (ICD) reaction of the benzyl sulphide (12) as a key reaction.
- Kametani, Tetsuji,Kawamura, Kuniaki,Tsubuki, Masayoshi,Honda, Toshio
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p. 193 - 200
(2007/10/02)
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- ANHYDROUS FERRIC CHLORIDE ADSORBED ON SILICA GEL INDUCED RING ENLARGEMENT OF TERTIARY CYCLOBUTANOLS. SYNTHESIS OF ISOLAUROLENE AND DERIVATIVES, CAMPHOLENIC ETHER AND (+/-) CUPARENE
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The reagent obtained by mixing anhydrous FeCl3 and silica gel induced, in dry medium, dehydration and specific C4 -> C5 ring enlargement of tertiary cyclobutanols, cyclization of olefinic alcohols and cleavage of tetrahydropyranyl ethers.
- Fadel, A.,Salauen, J.
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p. 413 - 420
(2007/10/02)
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- Direct Geminal Dimethylation of Ketones and Exhaustive Methylation of Carboxylic Acid Chlorides Using Dichlorodimethyltitanium
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The reaction of ketones with an excess of (CH3)2TiCl2 (6) leads to the replacement of the carbonyl oxygen atom by two methyl groups.This mild method of direct geminal dimethylation involves Grignard-type addition followed by formation of tertiary carbocations which are captured by methyltitanium species.Additional functional groups such as primary alkyl chlorides, thioethers, aromatics, ethers and esters are tolerated, but not thioketals.The procedure has been applied to the synthesis of (+/-)-cuparene (44).Similarly, carboxylic acid chlorides are converted to tert-butyl derivatives.
- Reetz, Manfred T.,Westermann, Juergen,Kyung, Suk-Hun
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p. 1050 - 1057
(2007/10/02)
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- Synthesis of α-Cuparenone
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Ethyl 2-carbethoxy-3-p-tolylpropanoate (VII) on Michael reaction with acrolein followed by acetal formation furnishes acetal-malonate (IX).The diacid (X), obtained by hydrolysis of IX, is warmed with lead tetraacetate-pyridine mixture, and the resulting p
- Anand, R. C.,Ranjan, H.
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p. 1054 - 1057
(2007/10/02)
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- Stereochemical Evidence for a Carbonium Ion Rearrangement during Reaction of Dimethyltitanium Dichloride with a Ketone
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Racemization during the reaction of dimethyltitanium dichloride with the 2,2-disubstituted cyclopentanone (-)-3 of high enantiomeric purity provides stereochemical evidence for a carbonium ion rearrangement during this dimethylation process.
- Posner, Gary H.,Kogan, Timothy P.
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p. 1481 - 1482
(2007/10/02)
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