Search results
Results from the WOW.Com Content Network
Reaction mechanism for the bromination of acetone while in the presence of acetic acid. Basic (in aqueous NaOH): Reaction mechanism for the bromination of acetone while in the presence of aqueous NaOH. In acidic solution, usually only one alpha hydrogen is replaced by a halogen, as each successive halogenation is slower than the first.
The photo-Favorskii reaction has been used in the photochemical unlocking of certain phosphates (for instance those of ATP) protected by p-hydroxyphenacyl groups. [13] The deprotection proceeds through a triplet diradical ( 3 ) and a dione spiro intermediate ( 4 ) although the latter has thus far eluded detection.
Ring expansion and ring contraction reactions expand or contract rings, usually in organic chemistry. The term usually refers to reactions involve making and breaking C-C bonds, [1] Diverse pathways lead to these kinds of reactions. Many of these reactions are primarily of theoretical or pedagoogical interest, but some are very useful.
The reaction is much slower with ketones than aldehydes. [42] For example, in Nicolaou's epothilones synthesis, asymmetric allylboration (with an allylborane derived from chiral alpha-pinene ) is the first step in a two-carbon homologation to acetogenin : [ 43 ]
In chemistry, the haloform reaction (also referred to as the Lieben haloform reaction) is a chemical reaction in which a haloform (CHX 3, where X is a halogen) is produced by the exhaustive halogenation of an acetyl group (R−C(=O)CH 3, where R can be either a hydrogen atom, an alkyl or an aryl group), in the presence of a base.
For example, a change of reaction medium from hexane to water increases the rate of tert-Butyl chloride (t-BuCl) heterolysis by 14 orders of magnitude. [5] This is caused by very strong solvation of the transition state. The main factors that affect heterolysis rates are mainly the solvent's polarity and electrophilic as well as its ionizing power.
The Buchner–Curtius–Schlotterbeck reaction is the reaction of aldehydes or ketones with aliphatic diazoalkanes to form homologated ketones. [1] It was first described by Eduard Buchner and Theodor Curtius in 1885 [ 2 ] and later by Fritz Schlotterbeck in 1907. [ 3 ]
The reduction of α-halo ketones generates a variety of product structures that may exhibit unique substitution patterns and reactivity. For instance, reduction of α,α'-dihalo ketones leads to 2-oxyallyl metal complexes, which participate in [4+3] and [3+2] cycloaddition reactions as the 2π component.