Which one of the following reactions will not | vedclass

Name: Exam Paper Generator | JEE NEET Paper Generator | Vedclass
Brand: Vedclass
Rating: 5 (35 reviews)

Question

(D) The Williamson ether synthesis involves the reaction of an alkoxide ion with an alkyl halide. For the reaction to proceed via $S_N2$ mechanism to

Vedclass · Accepted Answer

$iso-BuO^{\ominus} Na^{\oplus} + sec-BuBr \rightarrow$ Elimination product

Vedclass · Answer

(D) The Williamson ether synthesis involves the reaction of an alkoxide ion with an alkyl halide. For the reaction to proceed via $S_N2$ mechanism to form an ether,the alkyl halide should ideally be primary. If the alkyl halide is secondary or tertiary,the strong base (alkoxide) will prefer to undergo an $E2$ elimination reaction rather than $S_N2$ substitution. In option $A$,${}^{t}BuO^{\ominus}$ is a bulky base and $EtBr$ is a primary halide,so $S_N2$ is possible,but often elimination competes. However,in option $D$,$iso-BuO^{\ominus}$ is a base reacting with $sec-BuBr$ (a secondary alkyl halide). Due to steric hindrance and the nature of the secondary halide,the $E2$ elimination reaction is highly favored over $S_N2$ substitution,leading to alkene formation as the major product instead of the desired ether.

Which one of the following reactions will not lead to the desired ether formation in major proportion? (iso-$Bu$ $\Rightarrow$ isobutyl,sec-$Bu$ $\Rightarrow$ sec-butyl,$nPr$ $\Rightarrow$ $n$-propyl,${}^{t}Bu$ $\Rightarrow$ tert-butyl,$Et$ $\Rightarrow$ ethyl)

Similar Questions

Consider the reaction sequence:
Dimethyl ketone $\xrightarrow[(ii) H_2O]{(i) CH_3MgCl} X$ $\xrightarrow[(ii) CH_3Br]{(i) Na} Y$
How many $sp^3$ carbons are present in $Y$?

Assertion : Iodide ion combines with smaller group to avoid steric hindrance.
Reason : With $HI$,anisole gives iodobenzene and methyl alcohol.

$C_2H_5OH$ $\xrightarrow{Na} P$ $\xrightarrow{CH_3-Cl} Q$; $Q$ is

What is obtained when sodium ethoxide and ethyl iodide are heated together?

Which one of the following methods is used to prepare $Me_{3}COEt$ with a good yield?

Vedclass Test Series

Exam Paper Generator

Online Exam Module