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A halogen addition reaction is a simple organic reaction where a halogen molecule is added to the carbon–carbon double bond of an alkene functional group. [1] The general chemical formula of the halogen addition reaction is: C=C + X 2 → X−C−C−X (X represents the halogens bromine or chlorine, and in this case, a solvent could be CH 2 ...
Iodination and bromination can be effected by the addition of iodine and bromine to alkenes. The reaction, which conveniently proceeds with the discharge of the color of I 2 and Br 2, is the basis of the analytical method. The iodine number and bromine number are measures of the degree of unsaturation for fats and other organic compounds.
General overview of addition reactions. Top to bottom: electrophilic addition to alkene, nucleophilic addition of nucleophile to carbonyl and free-radical addition of halide to alkene. Depending on the product structure, it could promptly react further to eject a leaving group to give the addition–elimination reaction sequence.
Alkenes reliably add bromine without catalysis to give the vicinal dibromides: RCH=CH 2 + Br 2 → RCHBrCH 2 Br. Aromatic compounds undergo bromination simultaneously with evolution of hydrogen bromide. Catalysts such as AlBr3 or FeBr3 are needed for the reaction to happen on aromatic rings.
In organic chemistry, syn-and anti-addition are different ways in which substituent molecules can be added to an alkene (R 2 C=CR 2) or alkyne (RC≡CR).The concepts of syn and anti addition are used to characterize the different reactions of organic chemistry by reflecting the stereochemistry of the products in a reaction.
Adding the hydrogen ion to one carbon atom in the alkene creates a positive charge on the other carbon, forming a carbocation intermediate. The more substituted the carbocation, the more stable it is, due to induction and hyperconjugation. The major product of the addition reaction will be the one formed from the more stable intermediate.
Many halonium ions have a three-atom cyclic structure, similar to that of an epoxide, resulting from the formal addition of a halogenium ion X + to a C=C double bond, as when a halogen is added to an alkene. [1] The formation of 5-membered halonium ions (e.g., chlorolanium, bromolanium ions) via neighboring group participation is also well ...
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 ...