Search results
Results from the WOW.Com Content Network
Darzens halogenation is the chemical synthesis of alkyl halides from alcohols via the treatment upon reflux of a large excess of thionyl chloride or thionyl bromide (SOX 2) in the presence of a small amount of a nitrogen base, such as a tertiary amine or pyridine or its corresponding hydrochloride or hydrobromide salt.
The Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and a deprotonated alcohol . This reaction was developed by Alexander Williamson in 1850. [ 2 ] Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an S N 2 reaction .
Tetrafluoroethane (a haloalkane) is a colorless liquid that boils well below room temperature (as seen here) and can be extracted from common canned air canisters by simply inverting them during use. The haloalkanes (also known as halogenoalkanes or alkyl halides ) are alkanes containing one or more halogen substituents. [ 1 ]
In general, the reaction of a haloalkane with potassium hydroxide can compete with an S N 2 nucleophilic substitution reaction by OH − a strong, unhindered nucleophile. Alcohols are however generally minor products. Dehydrohalogenations often employ strong bases such as potassium tert-butoxide (K + [CH 3] 3 CO −).
Arrow-pushing mechanism for the Darzens reaction. If the starting halide is an α-halo amide, the product is an α,β-epoxy amide. [8] If an α-halo ketone is used, the product is an α,β-epoxy ketone. [2] Any sufficiently strong base can be used for the initial deprotonation.
The Finkelstein reaction, named after the German chemist Hans Finkelstein, [1] is a type of S N 2 reaction (substitution nucleophilic bimolecular reaction) that involves the exchange of one halogen atom for another.
The necessary α-halo sulfones are accessible through oxidation of the corresponding α-halo sulfides with peracids such as meta-chloroperbenzoic acid; oxidation of sulfides takes place selectively in the presence of alkenes and alcohols. α-Halo sulfides may in turn be synthesized through the treatment of sulfides with halogen electrophiles such as N-chlorosuccinimide or N-bromosuccinimide.
A reaction mechanism was first introduced by Christopher Ingold et al. in 1940. [3] This reaction does not depend much on the strength of the nucleophile, unlike the S N 2 mechanism. This type of mechanism involves two steps. The first step is the ionization of alkyl halide in the presence of aqueous acetone or ethyl alcohol.