- Double-Bond Isomerization: Highly Reactive Nickel Catalyst Applied in the Synthesis of the Pheromone (9 Z,12 Z)-Tetradeca-9,12-dienyl Acetate
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A highly reactive nickel catalyst comprising NiCl2(dppp) or NiCl2(dppe) with zinc powder, ZnI2 and Ph2PH, was applied in the isomerization of terminal alkenes to Z-2-alkenes. The double-bond geometry of the 2-alkene can be controlled via the reaction temperature to yield the 2-Z-alkenes in excellent yields and high Z-selectivities. The formation of other constitutional isomers, such as 3-alkenes, is suppressed on the basis of the proposed mechanism via a 1,2-hydride shift from the metal to the Ph2P ligand. The nickel-catalyzed isomerization reaction was then applied in the synthesis of (9Z,12Z)-tetradeca-9,12-dienyl acetate, a pheromone with a 2Z,5Z-diene subunit.
- Weber, Felicia,Schmidt, Anastasia,R?se, Philipp,Fischer, Michel,Burghaus, Olaf,Hilt, Gerhard
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supporting information
p. 2952 - 2955
(2015/06/30)
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Coupling reactions of lithium compounds, (Z)-carbonyl olefination of phosphonium ylides and 'crossed' Wittig olefination of bisylides are the key reaction steps in the synthesis principle for nonconjugated, bisolefinic Lepidoptera pheromones and structural analogs. Double unsaturated (E,Z)- and (E,E)-1-vinyl halides are converted into the corresponding (E,Z)- and (E,E)-1-vinyl lithium compounds and coupled selectively to (E,Z)- and (E,E)-alkadienols, alkadienals and alkadienyl acetates with different carbon chain length, geometry and relative positions of double bonds. 'Crossed' Wittig reactions of 1,ω-alkylidene bisylides with two different alkanals gives rise to the formation of corresponding (Z,Z)-dienic sex attractants and derivatives. A monounsaturated (E)-1-vinyl iodide is the synthon for the preparation of an (E)-alkenyl bromide which is converted to an (E)-alkenyl phosphonium salt and (Z)-selectively olefinated to (Z,E)-isomers of moth sex pheromones.
- Bestmann,Zeibig,Vostrowsky
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p. 1039 - 1047
(2007/10/02)
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- SYNTHESES WITH SULFONES XLVII : STEREOSELECTIVE ACCESS TO 1,3- AND 1,4-DIENES THROUGH HYDROGENOLYSIS OF BENZENESULFONYLDIENES. APPLICATION TO PHEROMONE SYNTHESIS.
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The stereospecific reduction of EE 2-benzenesulfonyl-1,3-dienes to ZE 1,3-dienes with Grignard reagents under transition metal catalysis is described.Hydrogenolysis of the sulfonyl moiety of 2-benzenesulfonyl-1,4-dienes to ZE 1,4-dienes with sodium dithionite is reported.These techniques have been applied to the stereoselective synthesis of (7E, 9Z) dodecadienyl acetate 3d, (9Z, 11E) tetradecadienyl acetate 3e and (9Z, 12E) tetradecadienyl acetate, 6b.
- Cuvigny, T.,Penhoat, C. Herve Du,Julia, M.
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p. 859 - 872
(2007/10/02)
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- Pheromones, XXXV. - Stereoselective Syntheses of 1,4-Alkadienes
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The stereoselective synthesis of 1,4-alkadienes via Julia synthesis, Wittig reaction, Crombie synthesis and methylene interruption of conjugated alkadienylphosphonates is described.
- Bestmann, Hans Juergen,Koschatzky, Karl-Heinrich,Plenchette, Alain,Suess, Joachim,Vostrowsky, Otto
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p. 536 - 544
(2007/10/02)
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