- Process for the preparation of butyrolactones
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The present invention relates to a process for the preparation of γ-butyrolactones.
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Page/Page column 7
(2008/06/13)
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- Thermal pericyclic tandem reactions
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Gas phase thermal isomerizations of twelve acetylenic systems, all of which can in principle undergo two successive pericyclic steps, are described. The substrates, the syntheses and spectroscopic properties of which are presented, are formal derivatives of but-2-yne, with different functional groups in the 1- and the 4-positions. The Cope, Claisen, Claisen ester, retro-ene, 1,5-hydrogen shift, and 1,5-homo hydrogen-shift processes were employed as the pericyclic steps from which the tandem processes were composed. The compositions of the pyrolysates obtained were determined over broad temperature ranges, and the mechanisms of the individual steps producing the pyrolysis products are discussed.
- Hopf, Henning,Wolff, Joachim
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p. 4009 - 4030
(2007/10/03)
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- A highly efficient synthetic route to (-)-furaquinocin C
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The first total synthesis of (-)-furaquinocin C, a member of the furaquinocin family of cytotoxic antibiotics, has been achieved. Central features of the successful synthetic strategy include Dieis-Alder construction of the furanonaphthoquinic skeleton and sequential cuprate- mediated conjugate additions to an α,β-unsaturated lactone. The synthetic route proved remarkably efficient requiting only six steps from (R)-(+)- angelicalactone, and utilizing a mere four reaction vessels. This stereospecific construction of (-)-furaquinocin C confirms earlier assignments of absolute and relative stereochemistry for the furaquinocins and also constitutes completion of a formal synthesis of (-)-furaquinocin F.
- Smith III, Amos B.,Sestelo, José Pérez,Dormer, Peter G.
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p. 1315 - 1328
(2007/10/03)
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- Process for the preparation of substituted furanones
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This invention relates to an improved process for the preparation of 3-acyl-5-alkyldihydro-2(3H)-furanones according to the following reaction scheme: STR1 wherein R and R1 are hydrogen or alkyl and R2 is a hydrocarbon or -O-hydrocarbon radical of from 1 to 20 carbon atoms and X is a leaving group.
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- Improved process for the preparation of substituted furanones
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This invention relates to an improved process for the preparation of 3-acyl-5-alkyldihydro-2(3H)-furanones according to the following reaction scheme: wherein R and R1 are hydrogen or alkyl and R2 is a hydrocarbon or -0-hydrocarbon radical of from 1 to 20 carbon atoms and X is a leaving group.
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- SYNTHESIS OF SINGLE ISOMERS (E OR Z) OF PROTECTED γ,δ-UNSATURATED KETONES BY THE HORNER-WITTIG REACTION
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The lithium derivative of the γ-diphenylphosphinoyl ketal (10a) added to aldehydes and ketones to give stable Horner-Wittig intermediates (11) which were separated and converted into single isomers (E or Z) or γ,δ-unsaturated ketals (12). erythro-Adducts (11) and hence Z-(12), were selectively formed by addition of aldehydes and threo adducts (11), and hence E-(12), by reduction of the corresponding α-diphenylphosphinoyl ketones (13), prepared by acylation of the same γ-diphenylphosphinoyl ketal (10a).
- Cornish Christopher A.,Warren, Stuart
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p. 2585 - 2598
(2007/10/02)
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- SYNTHESIS OF ALL OF THE FOUR ENERGETICALLY POSSIBLE STEREOISOMERS OF 7-ETHYL-2-METHYL-1,6-DIOXASPIRODECANE; A PHEROMONE PRODUCED BY BEES PARAVESPURA VULGARIS L. AND ANDRENA HAEMORRHOA F.
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All of the four energetically possible stereoisomers of 7-ethyl-2-methyl-1,6-dioxaspirodecane were synthesized starting from ethyl (S)-lactate and dimethyl (S)-malate or methyl (R)-β-hydroxy-valerate employing dianion alkylation as the key-step.
- Mori, Kenji,Ikunaka, Masaya
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p. 3471 - 3480
(2007/10/02)
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