Q11P. Question: Show how you would syn... [FREE SOLUTION]

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Chapter 20: Q11P. (page 1057)

Question: Show how you would synthesize the following carboxylic acids, using the indicated starting materials.
(a) $hex - 3 - yne 鈫� propanoic acid$
(b) $cis - cyclodecene 鈫� decanedioic acid$
(c ) $iodobenzene 鈫� phenylacetic acid$
(d) $pentan - 3 - ol 鈫� 2 - ethylbutanoic acid$
(e) $o - xylene 鈫� phthalic acid$
(f) $allyl bromide 鈫� but - 3 - enoic acid$

Short Answer

Expert verified

(a)

(b)

(c)

(d)

(e)

(f)

Step by step solution

Carboxylation of Grignard reagents

When added to carbon dioxide, Grignard reagents form magnesium salts of carboxylic acids.When treated with dilute acids, these salts protonate and form carboxylic acids.

Synthesis of carboxylic acids

(a) When hex-3-yne is treated with concentrated ${KMnO}_{4}$ or $O_{3} {/H}_{2} O$ , alkyne is oxidized to propanoic acid.

Synthesis of propanoic acid

(b) When cis-cyclodeceneis treated with concentrated ${KMnO}_{4}$ or heated with an acid, an alkene is oxidized to decanedioic acid.

Synthesis of decanedioic acid

(c) It forms a Grignard reagent when iodobenzene is treated with Mg in an ether solvent. Further, on treating with oxirane and heating with an acid, primary alcohol is formed. At last, in excess of NaOCl, alcohol is converted to phenylacetic

acid.

Synthesis of phenylacetic acid

(d) When pentan-3-ol is treated with ${PBr}_{3}$ , it forms 3-bromopentane. Further, on treating with Mg in the presence of an ether solvent and then with carbon dioxide, and at last on heating with an acid, it converts into 2-ethylbutanoic acid.

Synthesis of 2-ethylbutanoic acid

Synthesis of carboxylic acids

(e) When o-xylene is treated with concentrated ${KMnO}_{4}$ and heated with an acid, it forms phthalic acid.

Synthesis of phthalic acid

(f) When allyl bromide is treated with Mg in the presence of an ether solvent and further treated with carbon dioxide, and at last, when treated with acid, it forms but-3-enoic acid.