Consider the following reactions. From these reactions which reaction will give carboxylic acid as a major product ? (A) $R-C\equiv N \xrightarrow[\text{mild condition}]{(i)\ H^{+}/H_2O}$ (B) $R-MgX \xrightarrow[(ii)\ H_3O^{+}]{(i)\ CO_2}$ (C) $R-C\equiv N \xrightarrow[(ii)\ H_3O^{+}]{(i)\ SnCl_2/HCl}$ (D) $R\cdot CH_2\cdot OH \xrightarrow{PCC}$ (E) Choose the correct answer from the options given below :
Show Hint
Decide which of the reactions end in a carboxylic acid: nitrile partial hydrolysis, Grignard + CO2, Stephen, PCC, Rosenmund.
Step 1: Which step gives -COOH? Only oxidation of an aldehyde or carboxylation of a carbanion does.
Step 2: (B) $R{-}MgX + CO_2 \rightarrow RCOOMgX \xrightarrow{H_3O^+} RCOOH$: yes.
Step 3: (E) $C_6H_5COCl \xrightarrow{H_2/Pd{-}BaSO_4} C_6H_5CHO \xrightarrow{Br_2/H_2O} C_6H_5COOH$: yes.
Step 4: (A) mild hydrolysis stops at $RCONH_2$; (C) Stephen reaction gives $RCHO$; (D) PCC stops at $RCHO$: none gives the acid.
Step 5: B and E only, option (4).
Was this answer helpful?
0
Top Questions on Chemical Reactions of Aldehydes Ketones and Carboxylic Acids
can be subjected to Wolff-Kishner reduction to give
into 
