24834-34-2Relevant academic research and scientific papers
Ligand exchange reaction of sulfoxides in organic synthesis: A novel method for generation of magnesium enolates and its application to synthesis of α-halocarboxylic acid derivatives and α-haloaldehydes
Satoh,Kitoh,Onda,Takano,Yamakawa
, p. 4957 - 4972 (2007/10/02)
A new method for synthesis of α-halo(Cl, F)carboxylic acid derivatives and α-haloaldehydes is described. α-Halo-α-sulfinyl carboxylic acid, esters, and α-halo-α-sulfinyl aldehydes were easily prepared from aryl 1-haloalkyl sulfoxides and alkyl chloroformate and ethyl formate, respectively, in good yields. α-Chloro-α-sulfinyl amides were synthesized from (p-tolylthio)acetic acid. Ligand exchange reaction of the sulfinyl group of these acids, esters, amides, and aldehydes with ethylmagnesium bromide gave the magnesium enolates, which were treated with water to give α-halocarboxylic acid derivatives and α-chloroaldehydes in good yields. The magnesium enolates derived from the α-chloro-α-sulfinyl acid derivatives were trapped with carbonyl compounds to afford the adducts, which were transformed to α,β-epoxy carboxylic acid derivatives. Thermal elimination of the sulfinyl group in the α-halo-α-sulfinyl acid derivatives and the α-halo-sulfinyl aldehydes gave α-halo-α,β-unsaturated carboxylic acid derivatives and α-halo-α,β-unsaturated aldehydes in high yields.
Ligand Exchange Reaction of Sulfoxides in Organic Synthesis: A New Method for Generation of Magnesium Enolates of α-Chloro Carboxylic Acids and Their Derivatives
Satoh, Tsuyoshi,Kitoh, Yasushi,Onda, Ken-ichi,Yamakawa, Koji
, p. 2331 - 2334 (2007/10/02)
Treatment of α-chloro α-sulfinyl carboxylic acid derivatives with EtMgBr in THF at low temperature gave magnesium enolates of the α-chloro carboxylic acid derivatives.The enolates reacted with ketones and aldehydes to afford aldol compounds (or α,β-epoxy acids) in good yields. +"--"+ Key Words: sulfoxide, ligand exchange, magnesium enolate, aldol reaction, Darzen's reaction
Dianions Derived from α-Halo Acids. The Darzens Condensation Revisited
Johnson, Carl R.,Bade, Thomas R.
, p. 1205 - 1212 (2007/10/02)
The dianions of α-halo carboxylic acids are readily generated by the addition of the acids to 2 equiv of lithium diisopropylamide at low temperatures.When the mixture warms to room temperature dimeric products are formed.When aldehydes and ketones were added to the cooled solutions of the dianions and the reaction mixtures were allowed to warm to room temperature, followed by acid quench, glycidic acids were formed.The glycidic acids, per se, were often too unstable to be isolated and purified but could be analyzed by conversion to their methyl esters withdiazomethane.When the reactions were quenched prematurely, α-chloro-β-hydroxy carboxylic acids were isolated.Homologated aldehydes and ketones were obtained from the glycidic acids by catalytic and thermal decarboxylation methods.
