- (Alkenyl-η3-allyl)bis(η5-cyclopentadienyl)titanium Complexes
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Bis(η5-cyclopentadienyl)titanium hydride (Cp2TiH), presumably formed in situ from bis(η5-cyclopentadienyl)titanium dichloride (1) and isopropylmagnesium bromide (2) adds to the conjugated C=C bonds of the alkatrienes 4, 5, 25, 36, and 45 to give the (alkenyl-η3-allyl)bis(η5-cyclopentadienyl)titanium complexes 7 and 10, 8, 26, and 30, 37, 46.The complexes 7, 8, and 26 with the alkenyl group in position 1 isomerize to give the compounds 27, 28, and 29 in which the C=C bond is conjugated with the allyl group.Compound 37 which contains an alkenyl group in a meso-position does not isomerize.In the case of isomycoren (40), TiH addition occurs primarily to the isolated C=C bond followed by intramolecular cyclization to give the bis(η5-cyclopentadienyl)(1-cyclopentyl-η3-allyl)titanium complex 41.
- Lehmkuhl, Herbert,Fustero, Santos
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p. 1353 - 1360
(2007/10/02)
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- Monoterpenoid Synthesis by Transition Metal Catalyzed Coupling of Enediylmagnesium with C5-Organic Halides
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A series of isoprene coupling dimers bonded at 1-2, 1-3, 1-4, 2-4, 3-4, or 4-4 position was prepared by regiocontrolled catalysis of transition metals or without catalysts in the reaction of 2-methyl-2-butene-1,4-diylmagnesium or 3-methyl-2-butenylmagnesium chloride with C5-alkenyl halides.
- Kajihara, Yasushi,Ishikawa, Katsuhiro,Yasuda, Hajime,Nakamura, Akira
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p. 3035 - 3036
(2007/10/02)
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