Search results
Results from the WOW.Com Content Network
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 ...
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
An aldol condensation is a condensation reaction in organic chemistry in which two carbonyl moieties (of aldehydes or ketones) react to form a β-hydroxyaldehyde or β-hydroxyketone (an aldol reaction), and this is then followed by dehydration to give a conjugated enone. The overall reaction equation is as follows (where the Rs can be H)
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 condensation), which form alcohols as by-products. [5]
The aldol reaction (aldol addition) is a reaction in organic chemistry that combines two carbonyl compounds (e.g. aldehydes or ketones) to form a new β-hydroxy carbonyl compound. Its simplest form might involve the nucleophilic addition of an enolized ketone to another:
Intramolecular aldol reactions have been widely used in total syntheses of various natural products, especially alkaloids and steroids. An example is the application of an intramolecular aldol reaction in the ring closure step for total synthesis of (+)-Wortmannin by Shigehisa, et al. [5] (Figure 2).
The reaction is known as the Claisen reaction and was described by Claisen for the first time in 1890. Discovered the thermally induced rearrangement of allyl phenyl ether in 1912. He details its reaction mechanism in his last scientific publication (1925). In his honor, the reaction has been named the Claisen rearrangement.
In organic chemistry, an aldol is a structure consisting of a hydroxy group (-OH) two carbons away from either an aldehyde or a ketone. The name combines the suffix 'ol' from the alcohol and the prefix depending on the carbonyl group , either 'ald' for an aldehyde, or 'ket' for a ketone, in which case it referred to as a 'ketol'.