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3,3',5,5'-tetra-tert-butyldiphenoquinone, DPQ

The organic oxidant 3,3',5,5'-tetra-tert-butyldiphenoquinone (DPQ) is commercially available and can also be readily prepared by oxidation of the inexpensive o,o'-di-tert-butylphenol. DPQ is a two electron acceptor that forms o,o'-di-tert-p-bisphenol as product, which can easily be separated. Reoxidation using oxygen in the presence of base is possible in near quantitative yields, which means, that O2 can formally be considered as the terminal oxidant in these reactions. (M. S. Kharasch, B. S. Joshi, J. Org. Chem. 1957, 22, 1439. DOI)

Compared with benzoquinone, one of the advantages is the non-nucleophilic character of the reaction product. Thus, DPQ can be used in reactions with electrophiles without any interference.


Recent Literature


Cooperative carbene catalysis allows selective oxidative acylations of alcohols with aldehydes even in the presence of amino groups by using a readily available cheap organic oxidant. Quantum chemical calculations support the suggested mechanism.
S. De Sarkar, S. Grimme, A. Studer, J. Am. Chem. Soc., 2010, 132, 1190-1191.


A N-heterocyclic carbene catalyzes the oxidative esterification of various aldehydes in the presence of 3,3',5'5-tetra-tert-butyldiphenoquinone to yield hexafluoroisopropylesters, which are useful active esters for in situ amide bond formation. This transition metal-free organocatalytic system also enabled a mild oxidative azidation of aldehydes.
S. De Sarkar, A. Studer, Org. Lett., 2010, 12, 1992-1995.


A N-heterocyclic carbene catalyzes the oxidative esterification of various aldehydes in the presence of 3,3',5'5-tetra-tert-butyldiphenoquinone to yield hexafluoroisopropylesters, which are useful active esters for in situ amide bond formation. This transition metal-free organocatalytic system also enabled a mild oxidative azidation of aldehydes.
S. De Sarkar, A. Studer, Org. Lett., 2010, 12, 1992-1995.


The direct oxidative N-acylation reaction of primary amides with aryl/α,β-unsaturated aldehydes was achieved in the presence of an azolium salt and an inorganic base using 3,3′,5,5′-tetra-tert-butyldiphenoquinone as the oxidant. The reaction provides an efficient approach for the synthesis of N-sulfonylcarboxamides, N-sulfinylcarboxamides, and dicarboxyimides in good yield.
C. Zheng, Y. Liu, C. Ma, J. Org. Chem., 2017, 82, 6940-6945.


A broad range of functionalized Grignard compounds were coupled by using diphenoquinone as an electron acceptor. The oxidative dimerization of alkenylmagnesium reagents proceeds with complete retention of the stereochemistry.
A. Krasovskiy, A. Tishkov, V. del Amo, H. Mayr, P. Knochel, Angew. Chem. Int. Ed., 2006, 45, 5010-5014.


An N-heterocyclic carbene-catalyzed oxidative LUMO activation of the β-cabons of saturated carboxylic esters enables an efficient asymmetric access to lactams and lactones. The method introduces functional groups at the typically inert β-sp3 carbons of saturated esters. The use of HOBt as an additive improves both yields and enantioselectivities of the reactions.
B. Liu, W. Wang, R. Huang, J. Yan, J. Wu, W. Xue, S. Yang, Z. Jin, Y. R. Chi, Org. Lett., 2018, 20, 260-263.