Swern Oxidation—a nucleophilic substitution reaction

In 1976, when treating dimethyl sulfoxide (DMSO) with trifluoroacetic anhydride (TFAA) below -50°C in dichloromethane, D.Swern and co-workers discovered that trifluoroacetoxydimethylsulfonium trifluoroacetate was formed, which reacted rapidly with primary and secondary amines. The resulting alkoxydimethylsulfonium trifluoroacetates, when treated with trimethylamine, formed the corresponding aldehydes and ketones in high yields.

In 1978, oxalyl chloride was found to be more efficient than TFAA as an activating agent for DMSO in the oxidation of alcohols. Since then, the oxidation of primary or secondary alcohols using either DMSO and TFAA or oxalyl chloride has become known as the Swern Oxidation.

The total synthesis of the mytotoxic (+)-aseltoxin utilized the Swern oxidation, as did that of the marine dolabellane diterpene, (+)-deoxyneodolabelline. In the latter case, both Dess-Martin and Ley oxidations were tried, but the substrate suffered carbon-carbon bond cleavage.

Mechanism of the Swern oxidation:

Review available Thermo Scientific products for the Swern oxidation reaction:

Catalog # Name Size Price (USD)
A13280.36 Dimethyl sulfoxide, 99+% Each
41.65

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46.10
Save 4.45 (10%)
A13280.0E Dimethyl sulfoxide, 99+% Each
92.65

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103.00
Save 10.35 (10%)
A13280.0C Dimethyl sulfoxide, 99+% Each
283.65

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Ends: 30-Jun-2025

334.00
Save 50.35 (15%)
A13614.14 Trifluoroacetic anhydride, 99+% Each
26.65

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29.20
Save 2.55 (9%)
A13614.22 Trifluoroacetic anhydride, 99+% Each
57.65

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Ends: 30-Jun-2025

67.70
Save 10.05 (15%)
A13614.36 Trifluoroacetic anhydride, 99+% Each
193.65

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215.00
Save 21.35 (10%)
A13614.0E Trifluoroacetic anhydride, 99+% Each
698.65

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Ends: 26-Sep-2025

822.00
Save 123.35 (15%)
A12646.AK Triethylamine, 99% Each
38.60
A12646.AP Triethylamine, 99% Each
47.90
A12646.0F Triethylamine, 99% Each
116.65

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Ends: 26-Sep-2025

137.00
Save 20.35 (15%)
H31617.AE Oxalyl chloride, 2M soln. in dichloromethane Each
55.65

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62.20
Save 6.55 (11%)
H31617.AP Oxalyl chloride, 2M soln. in dichloromethane Each
113.65

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Ends: 26-Sep-2025

133.00
Save 19.35 (15%)
A18012.18 Oxalyl chloride, 98% Each
A18012.22 Oxalyl chloride, 98% Each
A18012.30 Oxalyl chloride, 98% Each
A18012.0B Oxalyl chloride, 98% Each

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