63721-05-1Relevant articles and documents
A biomimetic approach to taxol: Stereoselective synthesis of a 12-membered ring ene-epoxide
Takahashi, Takashi,Okabe, Tadashi,Iwamoto, Hajime,Hirose, Yoichiro,Yamada, Haruo,Doi, Takayuki,Usui, Shuji,Fukazawa, Yoshimasa
, p. 31 - 37 (1997)
The stereoselective synthesis of a taxol intermediate via a biomimetic route is described. Aldol condensation of γ-butyrolactone and citral derivatives generated three stereogenic centers at positions C1, C2, and C11 corresponding to taxol. Intramolecular alkylation of the cyanohydrin ether efficiently formed the 12-membered ring system in which stereoselective reduction, followed by directed epoxidation, afforded the key intermediate epoxide.
Methyl 3,3-dimethyl-4-pentenoate production method
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Paragraph 0006; 0007; 0024, (2016/12/22)
The invention relates to a methyl 3,3-dimethyl-4-pentenoate production method and belongs to the technical field of pyrethrin insecticide synthesis. Through a reaction rectification technology, isomerization and Claisen rearrangement reactions are simultaneously occur in a device comprising a stirring reactor and a rectifying tower connected to the stirring reactor, the reaction product is refined to form a methyl 3,3-dimethyl-4-pentenoate product in the presence of a phosphoric acid catalyst, and the produced methanol is continuously separated from the rectifying tower. The production method is used for methyl 3,3-dimethyl-4-pentenoate synthesis and has the advantages of high yield and low production cost.
POLYMERIZATION OF OLEFINS
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, (2008/06/13)
Olefins containing selected functional groups such as silyl, ether and alkenyl, and often containing a blocking group, may be copolymerized with unsubstituted olefins such as ethylene and propylene in the presence of certain coordination compounds of nickel or palladium. The resulting polymers are useful as molding resins, elastomers, in adhesives and for films.
A Synthesis of β-Necrodol Via A Palladium Catalyzed Reductive Enyne Cyclization
Trost, Barry M.,Braslau, Rebecca
, p. 1231 - 1234 (2007/10/02)
The Pd catalyzed reductive enyne cyclization provides an approach to control 1,3-diastereoselectivity and thereby provides a five step synthesis of β-necrodol, a key substituent of the defensive secretion of the red-lined carrion beetle.
Process for the preparation of γ-unsaturated carboxylates
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, (2008/06/13)
The invention concerns a process for the preparation of γ-unsaturated carboxylic acid methyl esters by reacting an allyl alcohol with an excess of trimethyl orthoacetate in the presence of an acidic catalyst. The process involves: the slow addition of the allyl alcohol to trimethyl orthoacetate heated to a temperature at or near its boiling point; removal of portion of the trimethyl orthoacetate from the reaction mixture by distillation; and heating the remaining reaction mixture at a temperature of 130° to 160° C. to complete the reaction.
Reactions of Methyl-Substituted Hex-5-enyl and Pent-4-enyl Radicals
Beckwith, Athelstan L. J.,Easton, Christopher J.,Lawrence, Tony,Serelis, Algirdas K.
, p. 545 - 556 (2007/10/02)
Relative and absolute kinetic data have been determined for ring closure of methyl-substituted hex-5-enyl radicals: 2-methyl-(10a), 3-methyl-(4a), 4-methyl-(5a), 2,2-dimethyl-(10c), 3,3-dimethyl-(4c) and 4,4-dimethyl-hex-5-enyl (5c) radicals, generated by interaction of tributylstannane with the corresponding bromides (1a)-(3a) and (1c)-(3c).Each radical undergoes regiospecific or highly regioselective 1,5-cyclization more rapidly than does the unsubstituted radical (4d).The rate enhancements, which arise mainly from lowering of the activation energy, can be rationalized in terms of the gem-dimethyl effect. 1,5-Ring closures of monosubstituted species are stereoselective: 2-methyl- and 4-methyl-hex-5-enyl radicals (10a) and (5a) give mainly trans products, whereas 3-methylhex-4-enyl radical gives mainly the cis.This behaviour reflects the effect of the substituent on the stabilities of cyclic transition complexes in chair-like conformations.Ring closure of 2,2-dimethylpent-4-enyl radical or of 3,3-dimethylpent-4-enyl radical (19) could not be detected.
Process for the preparation of styryl-cyclopropanecarboxylic acid esters and intermediate products for this process
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, (2008/06/13)
A process for the preparation of a styryl-cyclopropane-carboxylic acid ester of the formula STR1 in which R is C1-4 -alkyl or an alcohol radical customary in pyrethroids, R1 is alkoxy or alkylthio, either of which may be optionally substituted by halogen, R2 is hydrogen or alkoxy, or R1 and R2 together are optionally halogen-substituted alkylenedioxy, and R3 is hydrogen or chlorine, comprising reacting a compound of the formula STR2 with, respectively, one, two or three equivalents of a base at a temperature below 60° C. The products are insecticidally active when R is the residue of a pyrethroid-type alcohol. Various syntheses are given for the starting materials which are new.
