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NBS will react with alkenes 1 in aqueous solvents to give bromohydrins 2. The preferred conditions are the portionwise addition of NBS to a solution of the alkene in 50% aqueous DMSO, DME, THF, or tert-butanol at 0 °C. [3] Formation of a bromonium ion and immediate attack by water gives strong Markovnikov addition and anti stereochemical ...
In the Goldfinger mechanism, the purpose of the NBS is simply to maintain a very low concentration of molecular bromine, while in the Bloomfield mechanism, its purpose is the generation of the initial radical used in the reaction, [11] which again can be quite a difficult process. [12]
Due to its ability to function as an oxidizer, 1,4-benzoquinone can be found in methods using the Wacker-Tsuji oxidation, wherein a palladium salt catalyzes the conversion of an alkene to a ketone. This reaction is typically carried out using pressurized oxygen as the oxidizer, but benzoquinone can sometimes preferred.
Reactions of the excited sensitizer can involve electron or hydrogen transfer, usually with a reducing substrate (Type I reaction) or interaction with oxygen (Type II reaction). [21] These various alternative processes and reactions can be controlled by choice of specific reaction conditions, leading to a wide range of products.
The mechanism of epoxidation with dioxiranes likely involves concerted oxygen transfer through a spiro transition state. As oxygen transfer occurs, the plane of the oxirane is perpendicular to and bisects the plane of the alkene pi system. The configuration of the alkene is maintained in the product, ruling out long-lived radical intermediates.
The following is the reaction mechanism of a nucleophilic aromatic substitution of 2,4-dinitrochlorobenzene (1) in a basic solution in water. Nucleophilic aromatic substitution Since the nitro group is an activator toward nucleophilic substitution, and a meta director, it is able to stabilize the additional electron density (via resonance) when ...
The five living U.S. presidents — Joe Biden, Donald Trump, Barack Obama, George W. Bush and Bill Clinton — reunited to honor the life and legacy of Jimmy Carter. On Thursday, Jan. 9, a date ...
This chemical reaction is typical of alkanes and alkyl-substituted aromatics under application of UV light. The reaction is used for the industrial synthesis of chloroform (CHCl 3), dichloromethane (CH 2 Cl 2), and hexachlorobutadiene. It proceeds by a free-radical chain mechanism.