Fukuyama reduction

Fukuyama reduction
Named after	Tohru Fukuyama
Reaction type	Organic redox reaction
Identifiers
Organic Chemistry Portal	fukuyama-reduction
RSC ontology ID	RXNO:0000680

The Fukuyama reduction is an organic reaction and an organic reduction in which a thioester is reduced to an aldehyde by a silyl hydride in presence of a catalytic amount of palladium. This reaction was invented in 1990 by Tohru Fukuyama.^[1] In the original scope of the reaction the silyl hydride was triethylsilane and the catalyst palladium on carbon:

Fukuyama reductions are used for the conversion of carboxylic acids (as thioester precursor) to aldehydes which is considered a difficult procedure because of the ease of secondary reduction to an alcohol.

Reaction mechanism

The basic reaction mechanism for this reaction takes place as a catalytic cycle:

Oxidative addition:
${\ce {{R-C(O)-SR}+ Pd^0 -> RC(O)-Pd^{II}-SR}}$
Transmetallation:
${\ce {{RC(O)-Pd^{II}-SR}+R3SiH->{RC(O)-Pd^{II}-H}+R3Si-SR}}$
Reductive elimination:
${\ce {RC(O)-Pd^{II}-H -> {RC(O)-H}+ Pd^0}}$

Scope

In a variation of the Fukuyama reduction the core BODIPY molecule has been synthesized from the SMe-substituted derivative:^[2] Additional reagents are copper(I)-thiophene-2-carboxylate (CuTC), Pd(dba)2 and tri(2-furyl)phosphine

In the related Fukuyama coupling the hydride is replaced by a carbon nucleophile.

References

^ Facile reduction of ethyl thiol esters to aldehydes: application to a total synthesis of (+)-neothramycin A methyl ether Tohru Fukuyama, Shao Cheng Lin, Leping Li J. Am. Chem. Soc., 1990, 112 (19), pp 7050–7051 doi:10.1021/ja00175a043
^ The Smallest and One of the Brightest. Efficient Preparation and Optical Description of the Parent Borondipyrromethene System. I. J. Arroyo, R. Hu, G. Merino, B. Z. Tang, E. Peña-Cabrera, J. Org. Chem. 2009, ASAP

[1] Facile reduction of ethyl thiol esters to aldehydes: application to a total synthesis of (+)-neothramycin A methyl ether Tohru Fukuyama, Shao Cheng Lin, Leping Li J. Am. Chem. Soc., 1990, 112 (19), pp 7050–7051 doi:10.1021/ja00175a043

[2] The Smallest and One of the Brightest. Efficient Preparation and Optical Description of the Parent Borondipyrromethene System. I. J. Arroyo, R. Hu, G. Merino, B. Z. Tang, E. Peña-Cabrera, J. Org. Chem. 2009, ASAP

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