- Pd(0)-catalyzed oxy- and aminoalkynylation of olefins for the synthesis of tetrahydrofurans and pyrrolidines
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The first Pd(0)-catalyzed intramolecular oxy- and aminoalkynylation of nonactivated olefins is reported. The reaction gives access to important tetrahydrofuran and pyrrolidine heterocycles with high diastereoselectivity. The unique synthetic potential of acetylenes is further exploited to access key building blocks for the synthesis of bioactive natural products.
- Nicolai, Stefano,Waser, Jerome
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supporting information; experimental part
p. 6324 - 6327
(2012/01/13)
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- An asymmetric synthesis of enantiopure chair and twist trans-cyclooctene isomers
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A pair of enantiopure chair and twist trans-cyclooctenes isomers were prepared by regioselective Sharpless asymmetric dihydroxylation of the central olefin of (E)-1,5,9-dectriene triene, with subsequent ring-closing metathesis to form an enantiomerically pure cis-cyclooctene. Epoxidation and ring-opening with lithium diphenylphosphide gives after oxidation two diastereomeric hydroxyphosphine oxides. Separate syn-elimination of these diastereomers gives enantiomerically pure chair and twist trans-cyclooctenes. A discussion of the molecular motion required to achieve the chair and twist isomers is discussed with reference to the X-ray crystal structure obtained for the hydroxyphosphine oxide leading to the chair trans-cyclooctene.
- Braddock, D. Christopher,Cansell, Gemma,Hermitage, Stephen A.,White, Andrew J.P.
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p. 3123 - 3129
(2007/10/03)
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- Synthesis of sub-units of marine polycyclic ethers by ring-closing metathesis and hydroboration of enol ethers
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A novel syntheses of Z-5-dezenol, Z-5-decenyl acetate, Z-7-dodecenol, Z- 7-dodecenyl acetate, Z-9-tricosene, Z-7,8-epoxy-methyloctadecane which are sex pheromone components of Lepidoptera and Diptera orders, have been realized via stereoselective cometathesis of 1,5-cyclooctadiene with ethylene in the presence of MoCls/SiO2-SnMe4 as a key reaction. The male cometathesis product, 1,Z-5,9-decatriene, has been converted into pheromone components monocloned above by regioselective partial hydroboration or hydrozirconation with help of 9-BBN and Cp2ZrHCl, correspondingly. The protonolysis of the obtained zirconosene derivative gave 1,Z-5-decadiene. Hydroboration-oxidation or hydroboration-C2-homologation of the latter but to Z-5- or Z-7 monoene pheromone components. Hydroboration-iodination of terminal double bond in 1,Z-5,9-decatriene, and further cross-coupling of the obtained iodine derivative with convenient lithium cuprates resulted in Z-9- tricosene, the main sex pheromone component of House Fly (Musca Domestica), or in 2-methyl-Z-7-octadecene, the presence of Gypsy Moth (Lymantria Dispar) sex attractant.
- Bykov, Victor I.,Butenko, Tamara A.,Petrova, Elena B.,Finkelshtein, Eugene Sh.
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p. 8249 - 8252
(2007/10/03)
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