Question

Construct a multistep synthetic route from ethylbenzene to (2-bromoethyl)benzene by dragging the appropriate items into the bins. Note that each bin will hold only one item, and not all reagents and structures will be used.

Answer 1

Answer:

(1)NBS, ROOR (2)$KOC(CH_{3})_{3}$ and (3)HBr, ROOR

Explanation:

Conversion of ethylbenzene to (2-bromoethyl)benzene involves three steps.

First step: allylic bromination of ethylbenzene in presence of NBS, ROOR. This step produces (1-bromoethyl)benzene.

Second step: E2 ellimination of HBr from (1-bromoethyl)benzene in presence of a strong base e.g. potassium t-butoxide [$KOC(CH_{3})_{3}$]. This step produces styrene

Third step: HBr addition to double bond in presence of HBr, ROOR (antimarkonikov addition of HBr). Thus step produces (2-bromoethyl)benzene.

Full reaction scheme has been shown below.