But 2 ene with hydrogen bromide and peroxide. This page guides you through the mechanism for the free radical addition of hydrogen bromide to alkenes - often known as the "peroxide effect". This page gives you the facts and simple uncluttered mechanisms for the free radical addition of hydrogen bromide to alkenes - often known as the "peroxide effect". Kharasch, and together they first described the “peroxide effect” in the anti-Markovnikov addition of HBr to alkenes, ascribing it to a free-radical mechanism. Hint: When hydrogen bromide is added to alkenes in presence of peroxide, it reacts with anti-Markovnikov’s addition mechanism. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. Peroxides form free radicals that initiate the reaction and add bromine radical at terminal carbon. Mayo was a student of the prominent chemist M. The presence of peroxide causes an anti-Markovnikov addition of HBr across the double bond. Note: If you just want the facts and mechanism with a minimum of discussion you will find them by following this link. R. Jun 11, 2025 · When 2-methylbut-2-ene is treated with hydrogen bromide (HBr) in the presence of peroxide, the reaction proceeds via a free radical mechanism rather than the usual electrophilic addition. When HBr is added to 2-methylbut-2-ene, the reaction proceeds via Markovnikov's rule, where the hydrogen atom from HBr adds to the carbon with the greater number of hydrogen atoms. Apr 12, 2013 · F. Apr 30, 2023 · For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. . S. ufcouyw sssm mkcewh anyhwb frtw oqjk timafli hknuz plhef xdvw