Single Choice

Grignard reagent is usually prepared by : $$R-X+Mg\xrightarrow {E{ t }_{ 2 }O} RMgX$$ Grignard reagent $$Ar-X+Mg\xrightarrow {E{ t }_{ 2 }O} ArMgX$$ Grignard reagent Grignard reagent acts as a strong base. Grignard reagent carry out nucleophilic attack in absence of acidic hydrogen. Grignard reagent form complex with its ether solvent. Complex formation with molecule of ether is an important factor in the formation and stability of Grignard reagent. Which of the following Grignard reagents are not possible ?

A$$HS - CH_{2} - CH_{2} - CH_{2}MgBr$$
B$$HO - CH_{2} - CH_{2} - CH_{2}MgBr$$
C$$NH_{2} - CH_{2} - CH_{2} - CH_{2}MgBr$$
DAll of these
Correct Answer

Solution

(A)$$\overset {\delta +}{H}-S-CH_2CH_2CH_2-MgBr \xrightarrow [reaction]{acid-base} BrMgS-CH_2CH_2CH_3$$

(B) $$H-O-CH_2CH_2CH_2MgBr \xrightarrow [reaction]{acid-base} BrMgO-CH_2CH_2CH_3$$

(C) $$\overset {\delta +}{H}-\underset {|}{N}-CH_2CH_2-CH_2-MgBr \xrightarrow [reaction]{acid-base} BrMg-\underset {|}{N}-CH_2CH_2CH_3$$
$$\delta^+ H$$ $$H$$

So, all of these Grignard reagent can take their own acidic hydrogen. Therefore all of these Grignard reagents are not possible.

SIMILAR QUESTIONS

Haloalkanes and Haloarenes

Which of the following can give a Grignard reagent when reacted with magnesium in dry ether ?

Haloalkanes and Haloarenes

Provide the structure of compound $$A$$ in the following reaction.

Haloalkanes and Haloarenes

The best yield of given product can be obtained by using which set of reactants $$X$$ and $$Y$$?

Haloalkanes and Haloarenes

Which of the following does not form Grignard reagent on reaction with $$Mg$$ in the presence of ether?

Haloalkanes and Haloarenes

An example of a sigma bonded organometallic compound is:

Haloalkanes and Haloarenes

An allylide on hydrolysis gives allylene. The alkaline earth metal cation of allylide dissolves in dry ether in the presence of alkyl halide to form Grignard reagent. The allylide is :

Haloalkanes and Haloarenes

In the following reaction, $$C_{6}H_{5}CH_{2}Br \underset {(ii)H_{3}O^{+}}{\xrightarrow {(i) Mg, Ether}} X$$, the product $$'X'$$ is:

Haloalkanes and Haloarenes

The final product obtained in the reaction is:

Haloalkanes and Haloarenes

Grignard reagent is prepared by the reaction between:

Haloalkanes and Haloarenes

The best yield of given product can be obtained by using which set of reactants $$X$$ and $$Y$$?

Contact Details