Question

1. Complete the following reaction with the correct intermediates and reagents: (4 pts) la. In the above reaction, why did the reaction stop after the second substitution (2 pts)? 1b. In the reaction depicted above, what was the role of HSO? (1 pt) le. What is the name of the cationic intermediate 3 and 5? (1 pt) ion 2. Why was PCC an adequate choice for the conversion of citronellol to citronellal (1 pt)? 3. What is one drawback of PCC (1 pt)? 4. During the PCC oxidation, the oxidation state of chromium goes from Cr (VI) to Cr(IV). Is Cr (VI) oxidized or reduced? (1 pts) 5. Based on the TLC plate illustrated below, what was the R value of the spot shown? (MUST SHOW WORK) (2 pts)

Answer 1

Complete reaction mechanism:

product

1a) After the second substitution further substitution stopped because the tertiary butyl group is too bulky so which will reduce the further substitution reaction.

1b) H2SO4 is a strong acid (proton donor) which acts as the dehydrating agent.

1c) Name of the formed cation is tertiary butyl cation.

Citronellol to citronellal conversion by PCC:

PCC OH . citronellol Citreonellal v=Co oxidation reaction Ho | Pcc Crivi) Pyridinium chlorick Erliv

  2. PCC is selectively oxidising the primary alcohol to aldehyde and secondary alcohol into ketone. PCC can not oxidise the aldehyde into acid. Over oxidation stopped by PCC.

3. PCC is a toxic chemical which is the drawback of PCC.

4. During PCC oxidation Cr (VI) change into Cr(IV) Here oxidation state of Cr decreased which means Cr is reduced in this reaction.