- A new synthetic route to 1,3,5-undecatrienes and fucoserratene
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A new procedure for preparing natural alkatrienes, fucoserratene and 1,3,5-undecatrienes, was developed. The key step of both syntheses is stereoselective formation of double bonds by the Wittig reaction starting from (E)-4,4-dimethoxy-2-butenal.
- Garibyan,Ovanesyan,Makaryan,Chobanyan
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p. 455 - 458
(2008/09/20)
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- The preparation and electrocyclic ring-opening of cyclobutenes: Stereocontrolled approaches to substituted conjugated dienes and trienes
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Thermal electrocyclic ring-opening of 4-alkyl-2-cyclobutene-1-carbaldehydes occurs at low temperature to give (2Z,4E)-alkadienals exclusively, and the process is exploited in transforming cis-3-cyclobutene-1,2-dimethanol 1 into a variety of naturally occurring 1,3,5-alkatrienes and 2,4-decadienoates. Desymmetrisation of 1 with Pseudomonas fluorescens lipase gives access to both enantiomers of 3-oxabicyclo[3.2.0]hept-6-en-2-one 4, for use in stereocontrolled routes to 6-oxygenated (2Z,4E)-alkadienals.
- Binns, Falmai,Hayes, Roy,Hodgetts, Kevin J.,Saengchantara, Suthiweth T.,Wallace, Timothy W.,Wallis, Christopher J.
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p. 3631 - 3658
(2007/10/03)
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- Use of cis-3-cyclobutene-1,2-dimethanol in stereoselective routes to some naturally occurring conjugated dienes and trienes
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Thermal electronic ring-opening of 4-alkyl-2-cyclobutene-1-carbaldehydes occurs at low temperature to give (2Z,4E)-alka-2,4-dienals exclusively, and this process is exploited en route to various isomeric naturally occurring 1,3,5-alkatrienes and 2,4-decadienoates from a single precursor, cis-3-cyclobutene-1,2-dimethanol 4.
- Hodgetts, Kevin J.,Saengchantara, Suthiweth T.,Wallis, Christopher J.,Wallace, Timothy W.
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p. 6321 - 6324
(2007/10/02)
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- Kinetics and Deuterium Kinetic Isotope Effects for the Thermal Sigmatropic Rearrangements of cis,cis-1,3,5-Octatriene
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Thermal isomerizations of cis,cis-1,3,5-octatriene at 60-111 deg C occur with activation parameters log A = 9.1 and Ea = 21.3 (to cis,cis,cis-2,4,6-octatriene) and Ea = 20.2 kcal mol-1 (to cis,cis,trans-2,4,6-octatriene).P
- Baldwin, John E.,Reddy, V. Prakash
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p. 8051 - 8056
(2007/10/02)
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- Stereospecific Syntheses and Spectroscopic Properties of Isomeric 2,4,6,8-Undecatetraenes. New Hydrocarbons from the Marine Brown Alga Giffordia mitchellae
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Giffordene (=(2Z,4Z,6E,8Z)-2,4,6,8-undecatetraene; 9f) and five stereoisomers are new C11H16 hydrocarbons from the marine brown alga Giffordia mitchellae.Their synthesis is based on non-stereoselective Wittig reactions of (E)-2-alkenals with appropriate acetylenic phosphoranes and subsequent chromatographic separation of the resulting (E/Z)-pairs.The uniform enynes (>98percent purity) are then stereospecifically reduced to (Z)-alkenes with Zn(Cu/Ag) in aq.MeOH at r.t. 13C- and 1H-NMR data of the new tetraenes are presented.Biosynthetically, giffordene (9f) originates from dodeca-3,6,9-trienoic acid via an unstable (3Z,5Z,8Z)-1,3,5,8-undecatetraene followed by a thermally allowed antarafacial 1,7-sigmatropic hydrogen shift to the (2Z,4Z,6E,8Z)-isomer 9f.
- Boland, Wilhelm,Schroer, Nora,Sieler, Christiane,Feigel, Martin
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p. 1025 - 1040
(2007/10/02)
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- 3-Oxiranylprop-2-enals as Synthetic Building Blocks. Easy and Stereoselective Synthesis of Naturally Occurring (E,Z)-1,3,5-Trienes and (E,Z)-2,4-Dienals, Pheromones and Flavour Components
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Witting reactions of the title compound (3) lead in one step to the (E,Z)-alkadienyloxiranes (6) and (7), useful starting materials for the preparation of pheromones and flavour components.
- Goldbach, Michael,Jaekel, Edgar,Schneider, Manfred P.
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p. 1434 - 1435
(2007/10/02)
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