Alcohol to Aldehyde/Ketone using PCC (Pyridinium Chlorochromate)

General Procedure:

To a solution of substrate (alcohol; 1 eq.) in CH₂Cl₂ (5 Vol) is added Pyridinium chlorochromate (1.2 eq.) in CH₂Cl₂ (5 Vol) and Celite at 0 ^oC and stirred at RT for 2 to 4 h. The reaction is monitored by TLC.

During the reaction progress, a brown tar-like material slowly gets precipitated out. The reaction mixture containing solids is filtered through Celite bed and the bed washed with CH₂Cl₂. The organic layers are combined, and washed with water (10 Vol) and brine solution (5 Vol). The resultant organic layer is dried over Na₂SO₄ and concentrated. The crude product shall be used for next reaction or if required, is purified by column chromatography

Note:

• PCC oxidation reaction is to be performed under anhydrous condition

• The addition of Celite or Molecular sieves helps in PCC reaction to make the brown tar-like material (side products from the reagent) not sticking to the bottom of the flask.

• The most preferable solvent is DCM

• PCC is acidic and hence it is not suitable for acid-labile substrates

• PCC is a toxic reagent

Typical Procedure:

• PCC Oxidation-1 (OrgSyn)

WO2005023787, page No. 5 (100 g batch)