25905-14-0Relevant articles and documents
PROCESSES FOR PREPARING 2-ISOPROPENYL-5-METHYL-4-HEXENOIC ACID, 2-ISOPROPENYL-5-METHYL-4-HEXEN-1-OL, AND A CARBOXYLATE ESTER THEREOF
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, (2021/10/22)
The present invention provides a process for preparing 2-isopropenyl-5-methyl-4-hexenoic acid of the following formula (4), comprising steps of: subjecting a Grignard reagent of the following general formula (1), wherein R1 represents a linear, branched, or aromatic monovalent hydrocarbon group having 1 to 8 carbon atoms, and X represents a chlorine atom, a bromine atom, or an iodine atom, and 1,1,1,3,3,3-hexamethyldisilazane to a deprotonation reaction to form a 1,1,1,3,3,3-hexamethyldisilazane derivative; and subjecting 2-methyl-3-buten-2-yl 3-methyl-2-butenoate of the following formula (3) to a rearrangement reaction in the presence of the 1, 1, 1,3,3,3-hexamethyldisilazane derivative to form 2-isopropenyl-5-methyl-4-hexenoic acid (4).
Enzymatic transesterification of racemic lavandulol: Preparation of the two enantiomeric alcohols and of the two enantiomers of lavandulyl senecioate
Zada, Anat,Harel, Miriam
, p. 2339 - 2343 (2007/10/03)
(R) and (S)-lavandulol are important compounds in the cosmetics industry and in pheromone research. The senecioyl ester of (S)-lavandulyl has recently been identified as the sex pheromone of the vine mealybug, a significant pest in vineyards. We herein report the preparation of the two enantiomers of lavandulol and lavandulyl senecioate, starting from racemic lavandulol. The preparation is based on a two-cycle enzymatic transesterification of racemic lavandulol with vinyl acetate using Porcine pancreas lipase. High enantioselectivity was achieved while the preparation yielded (R)-lavandulol with 96.7% ee and (S)-lavandulol with 92.6% ee.
A new synthesis of lavandulol via indium/palladium-mediated umpolung of vinyloxirane
Araki, Shuki,Kambe, Shinya,Kameda, Keiko,Hirashita, Tsunehisa
, p. 751 - 754 (2007/10/03)
A short synthesis of lavandulol is achieved by the In/Pd-mediated reaction of isopropenyloxirane with 3-methylbut-2-enal.
Highly S(N)2'-, (E)-, and antiselective alkylation of allylic phosphates. Facile synthesis of coenzyme Q10
Yanagisawa,Nomura,Noritake,Yamamoto
, p. 1130 - 1136 (2007/10/02)
Treatment of secondary allylic chlorides or allylic phosphates in tetrahydrofuran with prenyl Grignard reagent in the presence of CuCN · 2 LiCl gave geraniol or farnesol derivatives with high S(N)2' selectivity. Phosphate leaving groups were highly transstereoselective for the formation of (E,E)-farnesol derivatives. Furthermore, complete anti-S(N)2' selectivity was observed in the alkylation of optically active allylic phosphates. The present method appears to be an excellent carbon-carbon coupling reaction with high regio-, (E)-, and enantioselectivity. Coenzyme Q10 (ubiquinone 10) was efficiently synthesized using this methodology.
Selective 1,5-Diene Synthesis. A Radical Approach
Yanagisawa, Akira,Noritake, Yoshiyuki,Yamamoto, Hisashi
, p. 1899 - 1902 (2007/10/02)
A new synthetic route to 1,5-dienes is described.Irradiation of a mixture of allyl bromides and allyl sulfides in the presence of hexamethylditin gives the cross-coupled products selectively.
PRENYLATION OF OLEFINS IN NITROMETHANE
Julia, M.,Schmitz, C.
, p. 2485 - 2490 (2007/10/02)
The prenylation of isopentenyl and 3,3-dimethylallyl derivatives could be achieved efficiently with dimethyl vinyl carbinol and a variety of acids in nitromethane.Geraniol and isopentenylacetate led to farnesyl derivatives.
Model Studies of Terpene Biosynthesis. Intermolecular 1'-2 Electrophilic Condensation of 3-Methyl-2-butenyl Acetate
King, Chi-Hsin R.,Poulter, C. Dale
, p. 1413 - 1420 (2007/10/02)
The stereochemistry of the carbon-carbon bond-forming step in the electrophilic intermolecular 1'-2 condensation of 3-methyl-2-butenyl acetate (1-OAc) to yield lavandulyl acetate (2-OAc) was studied.Treatment of (1S)-3-methyl-2-butenyl acetate ((1S)-1-OAc) with aluminum trichloride in ethyl acetate gave labeled lavandulyl acetate (2-OAc) (30percent) and isoprene (65percent) as the major products.The configurations at C(1), C(2), and C(3) and the relative abundances of the diastereomers of 1-OAc were determined by converting the mixture to 3-(2'-propyl)-butyrolactone (3).The intensities of 1H resonances characteristic of each diastereomer were measured with the aid of Pirkle's chiral shift reagent, (S)-(+)-2,2,2-trifluoro-1-(9-anthryl)ethanol.The analysis showed that equal amounts of the (1S,2S,3R), (1S,2R,3R), (1S,2S,3S), and (1S,2R,3S) diastereomers of 2-OAc were obtained, signifying that the 1'-2 condensation was stereorandom at C(1) of the electrophilic isoprene unit.