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The Dieckmann condensation, where a molecule with two ester groups reacts intramolecularly, forming a cyclic β-keto ester. In this case, the ring formed must not be strained, usually a 5- or 6-membered chain or ring. Retro-Claisen condensation is the reverse of the title reaction, i.e., the base-induced cleavage of 2-ketoesters
The Dieckmann condensation is the intramolecular chemical reaction of diesters with base to give β-keto esters. [1] It is named after the German chemist Walter Dieckmann (1869–1925). [2] [3] The equivalent intermolecular reaction is the Claisen condensation. Dieckmann condensations are highly effective routes to 5-, 6-, and 7-member rings ...
Idealized scheme showing condensation of two amino acids to give a peptide bond. Many variations of condensation reactions exist. Common examples include the aldol condensation and the Knoevenagel condensation , which both form water as a by-product, as well as the Claisen condensation and the Dieckman condensation (intramolecular Claisen ...
The Claisen rearrangement is an exothermic, concerted (bond cleavage and recombination) pericyclic reaction. Woodward–Hoffmann rules show a suprafacial, stereospecific reaction pathway. The kinetics are of the first order and the whole transformation proceeds through a highly ordered cyclic transition state and is intramolecular.
The Claisen condensation involves the reaction of an ester enolate and an ester to form a beta-keto ester. Crossed Claisen condensations, in which the enolate and nucleophile are different esters, are also possible. An intramolecular Claisen condensation is called a Dieckmann condensation or
The reaction sequence in the related Hauser annulation is a Michael addition followed by a Dieckmann condensation and finally an elimination. The Dieckmann condensation is a similar ring closing intramolecular chemical reaction of diesters with base to give β-ketoesters. The Hauser donor is an aromatic sulfone or methylene sulfoxide with a ...
Intramolecular condensation reactions (3 P) R. Ring-condensations (1 C, 1 P) Pages in category "Condensation reactions" ... Claisen condensation;
It can be considered as a specific variation of the aldol condensation. This reaction is named after two of its pioneering investigators Rainer Ludwig Claisen and J. Gustav Schmidt, who independently published on this topic in 1880 and 1881. [1] [2] [3] An example is the synthesis of dibenzylideneacetone ((1E, 4E)-1,5-diphenylpenta-1,4-dien-3 ...