Answer to Question #96362 in Organic Chemistry for Megha Nautiyal

Question

Addition of HBr to conjugated diene gives 1,2 addition and 1,4 addition products. Explain.

Answer 1

Addition of HBr to conjugated diene (e.g. 1,3-butadiene) begins with the protonation of double bond which results in delocalized allyl carbocation. Both species of the carbocation attach anion of bromine to form 1,2- and/or 1,4-adducts.