Question

Predict the major organic product of the following reaction. Show all hydrogen atoms in the structures Use wedge-and-dash bonds to indicate stereochemistry at any asymmetric carbons Gradi Descr Polici Hoc HIG -CH=CH2 + H-Br You You up o You Ther HC

Answer 1

This is known as the addition reaction of alkene with HBr. In case (1), there is a formation of 3 ^o carbocation which is more stable carbocation and in case (2), there is a formation of 2 ^o carbocation takes place which is less stable cabocation. Since, there will not be any chiral center in the product, so it can be written in the normal form without any stereochemistry. So, the complete reaction with the arrow pushing mechanism is given as below:-

се -05 CHз. — ск= CH2 + HBл — сиз: СИ? — СИ Е СИ +9H— Вл 1 - сиз — а — спа — (2° Carbo cation) = less stable carbocation. О сиз Bя и сиз в“ и сиз ал , — — си; сиз CH3 CH3 (more stable product) (major product)

case - Э A n cn = CH 2 tb H-Br chanz си | сиз сиз Ф 2 + Bя - c— сня сну -cК — сH2 В. Сн, СН3 (minor product) (Less stable)