A Grignard reagent (A) and a haloalkene (B) react together to give (C). Compound (C) on heating with KOH yields a mixture of two geometrical isomers, (D) and (E), of which (D) predominates. (C) and (E) have the same molecular formula and (C) gives 1-bromo-3-phenyl propane on reaction with HBr in the presence of a peroxide. Give structures of (A), (B)and (C) and configuration of (D) and (E) with reasons.

A Grignard reagent (A) and a haloalkene (B) react together to give (C)

1.	A Grignard reagent (A) and a haloalkene (B) react together to give (C). Compound (C) on heating with KOH yields a mixture of two geometrical isomers, (D) and (E), of which (D) predominates. (C) and (E) have the same molecular formula and (C) gives 1-bromo-3-phenyl propane on reaction with HBr in the presence of a peroxide. Give structures of (A), (B)and (C) and configuration of (D) and (E) with reasons.
Answer» Solution :Since, (C) GIVES 1-bromo-3-phenylpropane on REACTION with HBr in the presence of a peroxide, therefore (C) is 3-phenylprop-1-ene. Because (C) and (E) have same MOLECULAR formula, therefore, they are isomers and the reaction is : (C) `overset(KOH)to(D)+(E)` ,it is an isomerisation reaction. So, (D) and (E) are 3-phenylprop-2-ene. Since, (C) is obtained by the reaction of a Grignard reagent (A) with haloalkene (B), therefore, (A)and (B) are: