Tungstate Photocatalyst

26 September, 2016 / by SK / in Reactions

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Overall Score4

Generality
Potential for Further Development
Criteria #3
Criteria #4
Criteria #5

General Characteristics

Tetrakis(tetrabutylammonium) decatungstate (TBADT) is an organic solvent-soluble polyoxometalate compound that can act as a C-H abstraction catalyst under UV-activated conditions.

It can promote the generation of carbon radicals from otherwise stable tertiary and secondary C-H bonds. The functionalization of C(sp³)-H bonds is possible by trapping the radicals by suitable reagents.

TBADT is drawing an attention as a useful catalyst for C-H activation, the rapidly-growing subfield of organic chemistry.

General References

Jaynes, B. L.; Hill, C. J. J. Am. Chem. Soc. 1993, 115, 12212. DOI: 10.1021/ja00078a089
Zheng, Z.; Hill, C. L. Chem. Commun. 1998, 2467. DOI: 10.1039/A805036H

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Hill, C. L. Synlett 1995, 127. DOI: 10.1055/s-1995-4883
Tanielian, C. Coord. Chem. Rev. 1998, 178-180, 1165. doi:10.1016/S0010-8545(98)00160-X
Hill, C. L. J. Mol. Catal. A 2007, 262, 2. doi:10.1016/j.molcata.2006.08.042
Fagnoni, M.; Dondi, D.; Ravelli, D.; Albini, A. Chem. Rev. 2007, 107, 2725. DOI: 10.1021/cr068352x
Tzirakis, M. D.; Lykakis, I. N.; Orfanopulos, M. Chem. Soc. Rev. 2009, 38, 2609. DOI:10.1039/b812100c

Reaction Mechanism

Ref: J. Phys. Chem. A 2003, 107, 1102.

Examples

An example where sunlight is used for the reaction has been reported, even though the reaction time is long.^[1]

Dehydrogenation of cyclooctane using TBADT-cobalt co-catalytic system.^[2]

Construction of a quaternary stereogenic center with an organocatalyst^[3]: TBADT catalyzes the abstraction of hydrogen from the catechol acetal.

Experimental Procedure

Preparation of TBADT.^[1]

Experimental Tips
References

Protti, S.; Ravelli, D.; Fagnoni, M.; Albini, A. Chem. Commun. 2009, 7351. DOI: 10.1039/B917732A
West, J. G.; Huang, D.; Sorensen, E. J. Nat. Commun. 2015, 6, 10093. doi:10.1038/ncomms10093
Murphy, J. J.; Bastida, D.; Paria, S.; Fagnoni, M.; Melchiorre, P. Nature 2016, 532, 218. doi:10.1038/nature17438