- Method for the Production of Optically Active 3-Alkyl Carboxylic Acids and the Intermediate Products Thereof
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An enantioselective method for producing optically active 3-alkyl carboxylic acids comprises transforming an optically active secondary alcohol into an optically active, activated compound by introducing a leaving group; reacting the activated compound with a malonic acid derivative to obtain an optically active, alkylated malonic acid compound, the reaction taking place exclusively in ether and/or carboxylic acid ester solvents and one or more aprotic polar solvents or alcohols as a cosolvent in a maximum proportion of 30 volume percent of total solvent, wherein the added cosolvent is not hexamethyl phosphoric acid triamide; the malonic acid compound is hydrolyzed if necessary to obtain the corresponding acid; and the corresponding acid is decarboxylated.
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- Camphorsulfonamide-Shielded, Asymmetric 1,4-Additions and Enolate Alkylations; Synthesis of a Southern Corn Rootworm Pheromone
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Using readily accessible 10-sulfonamido-isoborneols as regenerable, chiral auxiliaries, highly face-selective C-C-bond formations at Cα and Cβ of carboxylates could be conveniently achieved.Thus, conjugated additions of RCu to enoates (1->2) furnished, after saponification, β-substituted carboxylic acids 3 in 94-98 percent e.e.Similarly, propionates 12 yielded after deprotonation, enolate alkylation, and reductive ester cleveage the (R)-alcohols 15 in 78-98 percent e.e.The acid (+)-3e was converted to the pheromone (-)-11.
- Oppolzer, Wolfgang,Dudfield, Philip,Stevenson, Thomas,Godel, Thierry
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p. 212 - 215
(2007/10/02)
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