0000000000135013
AUTHOR
Enrique Sotoca
A Convenient Generation of Acetic Acid Dianion
The lithium enediolate of acetic acid can be generated efficiently, as a 0.5 M solution in THF, using lithium amides prepared from n-butyllithium in THF and either diethylamine or 1,3,3-trimethyl-6-azabicyclo-(3.2.1)-octane (AZA). Its reaction with carbonyl compounds leads to the corresponding β-hydroxy acids in good to moderate yields. Better yields are usually obtained when these amines are added in sub-stoichiometric amounts. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)
Reaction of lithium enediolates with perfluoroketene dithioacetals. Synthesis of α-trifluoromethyl γ-dicarboxylic acid derivatives
The reaction of perfluoroketene dithioacetals with dianions of carboxylic acids proceeds through the substitution of the vinylic fluoride. The preparative value of this reaction depends strongly on the reaction and work-up conditions, the optimisation of which led to use LDA as a base and multiple extraction techniques. The overall process may be considered as a formal synthesis of α-trifluoromethyl γ-dicarboxylic acid derivatives.
A new strategy for the synthesis of highly functionalised fluorinated compounds by reaction of lithium dianions of carboxylic acids with perfluoroketene dithioacetals
The reaction of perfluoroketene dithioacetal with lithium dienediolates of carboxylic acids proceeds at the ω position probably through an addition to the π system followed by elimination of the vinylic fluoride. The preparative value of this reaction depends strongly on the reaction and work-up conditions. The overall process lead to highly functionalised synthons containing a trifluoromethyl group.