- Helical primary structures of 1,3-spiroannelated five-membered rings: (±)-trispiro[4.1.1.4.2.2]heptadecane and (±)-tetraspiro[4.1.1.1.4.2.2.2]heneicosane
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A combination of three spiroannelation methods forms the basis for a synthesis of the first two helical hydrocarbons of 1,3-spiroannelated five-membered rings.
- Meyer-Wilmes, Imelda,Gerke, Ralf,Fitjer, Lutz
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experimental part
p. 1689 - 1696
(2009/05/26)
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- Formation of quaternary centres via iron allyl cations. Rapid entry into spirocyclic ring systems
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Ester-substituted allyltetracarbonyliron cations react with cycloalkylidene-type silyl enol ethers, silyl ketene acetals, and β-keto- esters to give 1,6-dicarbonyl compounds containing a newly formed quaternary centre. Selected condensation products are c
- Charlton, M. Anne,Green, James R.
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p. 965 - 974
(2007/10/03)
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- Synthesis of Cyclopentyl-Containing Spiro Ketones and Alcohols
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A new route to spiro ketones has been developed, based on the synthesis of 1,1,4-tricyano-2,2-polymethylenebutanes by electrochemical cross-coupling of 1,1-dicyano-2,2-polymethyleneethenes and acrylonitrile.These products were used to prepare hitherto unk
- Smirnov, Yu. D.,Tomilov, A. P.
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p. 308 - 310
(2007/10/03)
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- Organobis(cuprates): A New Class of Reagents and Method for Spiroannelation
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A one-step spiroannelation method applicable to the synthesis of the commonly encountered spirocyclic systems is described.The method involves the reaction of 3-halocycloalk-2-enones with a new type of cuprate reagent prepared from organodilithium reagents and copper thiophenoxide and is shown to provide efficient access to mspirononanes, spirodecanes, and spiroundecanes.The effects of temperature, concentration, and halogen variations on the efficiency of this process are reported for the reactions of 3-halo-5,5-dimethylcyclohex-2-enones 2a-c with 1,4-bis(CuSPhLi)butane (3).Under optimal conditions, chloroenone 2a reacts with reagent 3 to provide 9,9-dimethylspirodecan-7-one (5) in 96percent yield.The optimized conditions are found to apply generally to variously substituted halocyclopentenones and halocyclohexenones, providing the corresponding spirocyclic products in 76-93percent yield.The preparation of new dilithium reagents is also described along with their use in the spiroannelation procedure.The stability of the organobis(cuprates) is found to be influenced by the hybridization of the metal-bearing centers, with alkyl reagents more stable than alkenyl reagents.
- Wender, Paul A.,White, Alan W.
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p. 2218 - 2223
(2007/10/02)
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