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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
Discovered (1887) the condensation reaction of an ester with an activated methylene group, now known as the Claisen condensation. Synthesis of cinnamates by reacting aromatic aldehydes with esters. The reaction is known as the Claisen reaction and was described by Claisen for the first time in 1890.
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 ...
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 a powerful carbon–carbon bond-forming chemical reaction discovered by Rainer Ludwig Claisen. [1] The heating of an allyl vinyl ether will initiate a [3,3]-sigmatropic rearrangement to give a γ,δ-unsaturated carbonyl, driven by exergonically favored carbonyl CO bond formation Δ(Δ f H) = −327 kcal/mol (−1,370 kJ/mol).
Claisen may refer to: Rainer Ludwig Claisen, a German chemist Claisen rearrangement, a reaction of a allyl vinyl ether to a γ,δ-unsaturated carbonyl; Claisen condensation, a reaction between esters and carbonyl compounds in the presence of a strong base; Ireland–Claisen rearrangement, a chemical reaction of an allylic ester with strong base
Darzens condensation, Darzens–Claisen reaction, Glycidic ester condensation; Darzens halogenation; Darzens synthesis of unsaturated ketones; Darzens tetralin synthesis; Davis' reagent, Davis oxidation; Davis–Beirut reaction; De Kimpe aziridine synthesis; Dehydration reaction; Dehydrogenation; Delépine reaction; DeMayo reaction; Demjanov ...
The ACP-bound elongation group reacts in a Claisen condensation with the KS-bound polyketide chain under CO 2 evolution, leaving a free KS domain and an ACP-bound elongated polyketide chain. The reaction takes place at the KS n -bound end of the chain, so that the chain moves out one position and the elongation group becomes the new bound group.