Reaction of carboxylic acid to aldehyde

Fukuyama reduction

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Name reactions

Related reactions:Fukuyama clutch, Rosenmund

Organic Chemistry Portal: Fukuyama Reduction

The conversion of carboxylic acids to aldehydes is normally carried out in two steps: after reduction of the acid or an acid derivative to the alcohol, a mild oxidation takes place.

The Fukuyama reduction allows the simple and selective conversion of thioesters, which can be obtained e.g. by means of Steglich esterification, to the corresponding aldehydes.


mechanism

Compared to other methods of reducing carboxyls directly to aldehydes (e.g. DIBAL-H, Rosenmund), the Fukuyama reduction is a particularly mild alternative that tolerates a large number of functional groups.

The initial oxidative addition of Pd (0) to the C (sp2) -S bond is followed by transmetalation with Et3SiH. Reductive elimination of the acyl palladium hydride leads to the desired aldehyde.

Based on the foregoing mechanism, it was assumed that the replacement of Et3SiH allows the synthesis of ketones by means of a suitable organometallic reagent. Tests of different transition metal catalysts and organometallic compounds finally led to the conditions under which the "Fukuyama coupling" can be carried out.

For a review: T. Fukuyma, H. Tokuyama, Aldrichimica Acta2004, 37, 87.

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