question_answer

Which of the following synthesis gives 3 -methyl. 1- hexanol?  

A) 2- bromohexane \[\xrightarrow[{{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}]{Mg}\,\,\xrightarrow[(ii)\,{{H}_{3}}{{O}^{+}}]{(i)\,{{H}_{2}}C=\,O}\]

B) 2- bromopentane \[\xrightarrow[{{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}]{Mg}\]

C) 3- bromopantane \[\xrightarrow[{{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}]{Mg}\] \[\xrightarrow[(ii)\,{{H}_{3}}{{O}^{+}}]{(i)\,C{{H}_{3}}CH=O}\]

D) 1- bromobutane \[\xrightarrow[{{C}_{2}}{{H}_{5}}O{{C}_{2}}{{H}_{5}}]{Mg}\] \[\xrightarrow[(ii)\,{{H}_{3}}{{O}^{+}}]{(i)\,C{{H}_{3}}COC{{H}_{3}}}\]

Correct Answer: B

Solution :

[b] \[C{{H}_{3}}-\underset{Br}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{3}}\xrightarrow[{{({{C}_{2}}{{H}_{5}})}_{2}}O]{Mg}\] \[\xrightarrow{{{H}_{3}}{{O}^{+}}}C{{H}_{3}}-\underset{C{{H}_{2}}.C{{H}_{2}}OH}{\mathop{\underset{|}{\mathop{C}}\,}}\,H-C{{H}_{2}}-C{{H}_{2}}-C{{H}_{3}}\]