2,3-Dichloro-5,6-Dicyanobenzoquinone, DDQ
DDQ (2,3-dichloro-5,6-dicyanobenzoquinone), which is a stronger oxidant than 1,4-benzoquinone, is used as reagent for oxidative couplings and cyclization reactions and dehydrogenation of hydroaromatic compounds.
Recent Literature
Palladium-catalyzed oxygenation of allyl arenes or alkenes produce (E)-alkenyl
aldehydes with high yields. Allylic C-H bond cleavages occur under mild
conditions during this process. Mechanistic studies show that oxygen source is
water.
H. Chen, H. Jiang, C. Cai, J. Dong, W. Fu, Org. Lett., 2011,
13, 992-994.
Alkyl nitrites were prepared in good to excellent yields by treatment of
alcohols and thiols with
triphenylphosphine/2,3-dichloro-5,6-dicyanobenzoquinone/Bu4NNO2 in acetonitrile.
This method allows a selective conversion of primary alcohols in the presence of secondary and tertiary alcohols and thiols.
B. Akhlaghinia, A. R. Pourali, Synthesis,
2004,
1747-1749.
The deprotection of benzyl ethers was effectively realized in the presence of
2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) in MeCN under
photoirradiation using a long wavelength UV light.
M. A. Rahim, S. Matsumura, K. Toshima, Tetrahedron Lett., 2005,
46, 7307-7309.
A tandem TBAB-catalyzed substitution and a subsequent novel oxidative
rearrangement allow the synthesis of aryl or alkenyl nitriles from from benzyl
and allyl halides. The broad reaction scope and the mild conditions may make
these methods of use in organic synthesis.
W. Zhou, J. Xu, L. Zhang, N. Jiao, Org. Lett., 2010,
12, 2888-2891.
An inexpensive homogeneous iron catalyst enables a direct approach to alkenyl
nitriles from allylarenes or alkenes. Three C-H bond cleavages occur under the
mild conditions during this process, involving the cleavage of the allyl C(sp3)-H
bond as the rate-determining step.
C. Qin, N. Jiao, J. Am. Chem. Soc., 2010,
132, 15893-15895.
A reliable method for the direct construction of polysubstituted furans involves
Sn(II)- and Cu(I)-promoted addition/oxidative cyclization of alkynoates and
1,3-dicarbonyl compounds in the presence of
2,3-dichloro-5,6-dicyanobenzoquinone.
W. Liu, H. Jiang, M. Zhang, C. Qi, J. Org. Chem., 2010,
75, 966-968.
Various benzothiazoles were synthesized by the intramolecular cyclization of
thioformanilides using 2,6-dichloro-3,5-dicyano-1,4-benzoquinone (DDQ) in
dichloromethane at ambient temperature in high yields.
D. S. Bose, M. Idrees, B. Srikanth, Synthesis, 2007,
819-823.
A cobalt-catalyzed neutral Diels-Alder reaction of dienes derived from aldehydes
with terminal and internal alkynes, and DDQ oxidation of the dihydroaromatic
intermediates leads to regiochemically enriched biphenyl, terphenyl, and
silyl-functionalized benzene derivatives in good to excellent yields.
G. Hilt, M. Danz, Synthesis, 2008,
2257-2263.
The cobalt-catalyzed Diels-Alder reaction of alkynyl pinacol boronic esters with various dienes generates cycloadducts in very good regioselectivity. A reaction sequence (Diels-Alder reaction, Suzuki coupling, DDQ oxidation) was successfully performed as a one pot operation without isolation of the intermediates.
G. Hilt, K. I. Smolko, Angew. Chem. Int. Ed., 2003, 42,
2795-2797.
A concise one-pot synthesis of highly functionalized pyridines involves a formal
insertion of rhodium vinylcarbenoids derived from diazo compounds across the N-O
bond of isoxazoles. Upon heating, the insertion products undergo a rearrangement
to give 1,4-dihydropyridines. DDQ oxidation then affords the corresponding
pyridines in good yield.
J. R. Manning, H. M. L. Davies, J. Am. Chem. Soc., 2008,
130, 8602-8603.
