Jones Oxidation

What Is Jones Oxidation?

Jones oxidation is a classic organic chemistry oxidation reaction, mainly used to oxidize primary alcohols to carboxylic acids and secondary alcohols to ketones. The reaction was first reported by Ewart Jones in 1946.

Jones reagent is the core reagent of the reaction, usually a mixture of chromium trioxide (CrO₃), sulfuric acid (H₂SO₄) and acetone. During the reaction, chromium trioxide first reacts with sulfuric acid to form chromic acid (H₂CrO₄), which is further mixed with acetone and water to form Jones reagent. Potassium dichromate (K₂Cr₂O₇) can also be used instead of chromium trioxide.

• Reagents: Chromium trioxide or dichromate, acid (such as dilute sulfuric acid or acetic acid), water, acetone.
• Reactants: Primary alcohols (alkyl, aryl, alkenyl) or secondary alcohols (alkyl, aryl).
• Products: Carboxylic acids or ketones.
• Reaction type: Oxidation reaction.
• Related reaction: Corey-Kim oxidation, Dess-Martin oxidation, Swern oxidation.

Fig 1. Jones oxidation reaction and its mechanism. [1]

Mechanism of Jones Oxidation

The mechanism of Jones oxidation involves several steps. First, alcohol reacts with chromic acid trioxide to form chromium (VI) monoester. Then, the monoester may react with meso or racemic reaction in the presence of water to form the corresponding carbonyl compound (such as aldehyde or ketone), and further oxidize to carboxylic acid. During the reaction, hexavalent chromium is reduced to trivalent chromium, which can be indicated by color change (from orange to green).

Experimental Tips

Fig 2. Alternative reagents to Jones reagent. [1]

• Jones reagent has a certain acidity, but the reaction can be carried out under mild conditions. If ether is used as a solvent, the reaction can be carried out in a milder two-phase system.
• When the reactants contain double bonds, triple bonds or other acid-sensitive groups, Jones reagent can effectively avoid the oxidation of these groups.
• Jones oxidation reaction is fast and efficient, but the chromium (VI) compounds used are potentially carcinogenic, so they are gradually replaced by milder and more selective oxidants in modern organic synthesis, such as Collins reagent (chromium trioxide-pyridine complex), PCC (pyridinium chlorochromate) and PDC (pyridinium dichromate).
• Jones reagent can also be used for the oxidation of allyl alcohol to form α, β-unsaturated aldehyde compounds without further conversion into carboxylic acid.
• The OsO(Cat.)/Jones reagent system can oxidatively cleave olefin bonds to carboxylic acids.

Application Examples of Jones Oxidation

• Example 1: A modified Jones oxidation procedure using chromium oxide in concentrated sulfuric acid was used to obtain the carboxylic acid in high yields after working up the reaction mixture with cold ice water to precipitate out the pure carboxylic acid. [2]
• Example 2: Boc-protected erythro-β-hydroxyasparagine (eHyAsn) derivatives can be synthesized with a yield of 40% using Jones reagent. [3]

Fig 3. Synthetic examples via Jones oxidation reaction.

Related Products

CAS No.	Structure	Product
20039-37-6		Pyridinium dichromate
107017-73-2		1-(Boc-amino)cyclopropylmethanol
1123169-27-6		1-(Hydroxymethyl)cyclopropanecarboxamide
865451-85-0		3-Fluoro-3-hydroxymethyloxetane
45513-32-4		3-Aminomethyl-3-hydroxymethyloxetane
100306-33-0		(1R)-3-Chloro-1-phenyl-propan-1-ol
100306-34-1		(S)-(-)-3-chloro-1-phenyl 1-propanol
100760-04-1		(S)-1-(4-Bromophenyl)ethanol
101219-68-5		(R)-4-Fluoro-α-methylbenzyl alcohol
101219-69-6		(R)-1-(4-Cyanophenyl)ethanol
101219-71-0		(S)-1-(4-Cyanophenyl)ethanol
101219-73-2		(S)-4-Fluoro-α-methylbenzyl alcohol

References

1. Jie Jack Li. Name Reactions-A Collection of Detailed Mechanisms and Synthetic Applications, Sixth Edition, 2021, 386-388.
2. Almaliti J, et al. Journal of medicinal chemistry, 2016, 59(23), 10642-10660.
3. Esgulian M, et al. Organic letters, 2019, 21(7), 2378-2382.