However, if you want to selectively target an allylic carbon instead of an alkene bond or a/all tertiary carbons, you can use N-bromosuccinimide (NBS) in the presence of light (hv), which will target allylic carbon atoms and brominate them:

2011年6月10日 · In contrast, NBS (N-bromo succinimide) is a gleaming white crystalline solid and easy as pie to work with. But don’t be deceived. It packs a punch. It will do many of the same reactions as bromine – attached to the electron-withdrawing nitrogen of succinimide, the bromine has a partial positive charge and is therefore electrophilic.

N-Bromosuccinimide or NBS is a chemical reagent used in radical substitution, electrophilic addition, and electrophilic substitution reactions in organic chemistry. NBS can be a convenient source of Br •, the bromine radical. [1] NBS is commercially available. It can also be synthesized in the laboratory.

Another method for preparing alkyl halides from alkenes is with N-bromosuccinimide (NBS) in carbon tetrachloride (CCl 4) solution with the presence of light. The reaction specifically causes the substitution of bromine with a hydrogen attached to a carbon adjacent to the double bond - …

2013年11月25日 · So what is allylic and benzylic halogenation, anyway? Here’s an example of each. Take toluene and treat with either Br 2 in the presence of light, as per this procedure, or N-Bromosuccinimide (NBS) in the presence of a radical initiator + heat (or light) and one of the benzylic C–H bonds is replaced with C–Br.

2006年2月13日 · This report shows that benzylic bromination of hydrophobic substrates can be very effectively conducted by NBS in pure water at ambient temperature and with visible light as an activator, while the solubility of succinimide in water enables easy isolation of the products.

Step 1: The first step of allylic bromination is the homolytic cleavage of the N-Br bond (initiation) of the N -bromosuccinimide (NBS): Notice that the imide group can stabilize the radical by two additional resonance structures which helps to initiate the homolysis of the N-Br bond:

2014年9月28日 · My book asks me to consider reacting 1-butene with NBS and light. I know that NBS and light leads to radical formation, and this is an allylic/benzylic bromination problem.

Under radical conditions, alkanes containing allylic hydrogens enter into allylic halogenation. A particularly good reagent for allylic bromination is N -bromosuccinimide (NBS). The bromine reacts with the alkene by radical chain mechanism. The process is initiated by light that causes dissociation of Br 2 into bromine atom.

2023年12月22日 · Aerobic Benzylic C (sp 3)–H Bond Oxygenations Catalyzed by NBS under Visible Light Irradiation. An efficient photocatalytic oxidation of benzylic C (sp 3)–H bonds to ketones, esters, and amides has been developed using NBS as …