New Jobs:

- RS - Process Chem (Lilly)

- Scientist II (Deciphera)

- Director (Anokion)

- Scientist II (Arena)

Latest Internships:

- Cepheid

  (Chemistry R&D)

- E Ink

  (Chemistry)



Boc Deprotection

(TFA)







Mechanism:



Boc deprotection using trifluoroacetic acid (TFA)


Steps:

  1. The tert-butyl carbamate becomes protonated.
  2. Loss of the tert-butyl cation results in a carbamic acid.
  3. Decarboxylation of the carbamic acid results in the free amine.
  4. Protonation of amine under the acidic conditions provides the pdt as the TFA salt.

Key Points:

  1. The tert-butyl cation will either be quenched by a suitable trapping agent, deprotonate to form isobutylene (gas), or polymerize to form isobutylene oligomers.
  2. The CO2 gas that forms during the reaction should be allowed to escape. Don't run boc deprotections in closed systems.