47.3k views
2 votes
Predict the products formed when cyclohexanecarbaldehyde reacts with the following reagents:

(i) PhMgBr and then H₃O⁺
(ii) Tollen's reagent
(iii) Semicarbazide and weak acid
(iv) Excess ethanol and acid
(v) Zinc amalgam and dilute hydrochloric acid

User GingerBear
by
8.1k points

1 Answer

1 vote

Final answer:

Cyclohexanecarbaldehyde reacts with PhMgBr and H₃O+ to form a secondary alcohol, with Tollen's reagent to form a carboxylic acid, with semicarbazide to form a semicarbazone, with excess ethanol and acid to form an acetal, and with zinc amalgam and HCl to perform a Clem-mensen reduction resulting in a methyl group.

Step-by-step explanation:

When cyclohexanecarbaldehyde reacts with different reagents, the products formed are as follows:

  • PhMgBr and then H₃O+ will result in a secondary alcohol after a Grignard reaction where phenylmagnesium bromide adds to the carbonyl carbon, followed by acidification.
  • Tollen's reagent will oxidize the aldehyde to a carboxylic acid, specifically cyclohexanecarboxylic acid due to the silver mirror test.
  • Semicarbazide and weak acid would yield a semicarbazone, a derivative used for characterization of aldehydes.
  • Excess ethanol and acid will form an acetal, specifically a diethyl acetal, as a result of a reaction with two equivalents of ethanol.
  • Zinc amalgam and dilute hydrochloric acid, known as the Clem-mensen reduction, will reduce the aldehyde group to a methyl group, resulting in cyclohexane itself.
User Pushya
by
7.7k points