Various electron-rich aromatics could be smoothly converted into the corresponding aromatic nitriles in good yields by treatment with POCl3 and DMF, followed by molecular iodine in aqueous ammonia. The present reaction is a novel metal-free one-pot method for the preparation of aromatic nitriles from electron-rich aromatics.
S. Ushijima, H. Togo, Synlett, 2010, 1067-1070.
The commercially available, bench-stable dimethylmalononitrile (DMMN) enables an electrophilic cyanation of aryl Grignard or lithium reagents, generated in situ from the corresponding aryl bromides or iodides. The transnitrilation with DMMN avoids the use of toxic reagents and transition metals and occurs under mild reaction conditions, even for extremely sterically hindered substrates.
J. T. Reeves, C. A. Malapit, F. G. Buono, K. P. Sidhu, M. A. Marsini, C. A. Sader, K. R. Fandrick, C. A. Busacca, C. H. Senanayake, J. Am. Chem. Soc., 2015, 137, 9481-9488.
A t-Bu3P-monoligated Pd catalyst in MeCN-THF enabled an efficient general aromatic cyanation reaction under practicable conditions using NaCN as cyanide source, low-boiling recyclable solvents, and minimal quantities of inexpensive, nontoxic promoters. The reaction converts aromatic bromides to the corresponding nitriles in very good yield in short reaction time and tolerates many functional groups.
A. V. Ushkov, V. V. Grushin, J. Am. Chem. Soc., 2011, 133, 10999-11005.
In the presence of a highly effective Pd/CM-phos catalyst, an efficient cyanation of aryl chlorides proceeds at 70°C in general. Common functional groups such as keto, aldehyde, ester, nitrile and -NH2, and heterocyclic coupling partners are well tolerated. Moreover, a sterically hindered nonactivated ortho,ortho-disubstituted electrophile is shown to be a feasible coupling partner in cyanation.
P. Y. Yeung, C. M. So, C. P. Lau, F. Y. Kwong, Org. Lett., 2011, 13, 648-651.
In the palladium-catalyzed cyanation of aryl bromides utilizing the air-stable XantPhos-PdCl2 precatalyst, DIPEA as a reducing agent generates the active Pd(0) species in situ. Twenty-two substituted benzonitriles have been synthesized.
J. R. Coombs, K. J. Fraunhoffer, E. M. Simmons, J. M. Stevens, S. R. Wisniewski, Miao Yu, J. Org. Chem., 2017, 82, 7040-7044.
A mild and efficient, palladium-catalyzed reaction allows the cyanation of a wide range of (hetero)aryl halides and triflates at low catalyst loadings with mild temperatures ranging from rt to 40 °C. This mild method was applied to the synthesis of lersivirine, a reverse transcriptase inhibitor.
D. T. Cohen, S. L. Buchwald, Org. Lett., 2015, 17, 202-205.
A general catalyzed cyanation of hetero(aryl) chlorides using less toxic Zn(CN)2 as the cyanide source relies on the use of inexpensive NiCl2·6H2O/dppf/Zn as the catalytic system and DMAP as additive. The cyanation occurs under mild reaction conditions with wide functional group tolerance. The method was also successfully extended to aryl bromides and aryl iodides.
X. Zhang, A. Xia, H. Chen, Y. Liu, Org. Lett., 2017, 19, 2118-2121.
Hemilabile, bulky, and electron-rich MOP-type ligands enable a highly efficient palladium-catalyzed cyanation of unactivated aryl chlorides and even aryl mesylates with potassium hexacyanoferrate in good yields using t-BuOH and H2O as the solvent and K2CO3 as the base.
Y. Tu, Y. Zhang, S. Xu, Z. Zhang, X. Xie, Synlett, 2014, 25, 2938-2942.
A trans-spanned palladium has efficiently and selectively catalyzed the cyanation of aryl halides. The suggested reaction conditions are mild, exhibit good scope of substrates, and circumvent the need for an inert atmosphere and amine co-ligands.
O. Grossman, D. Gelman, Org. Lett., 2006, 8, 1189-1191.
K4[Fe(CN)6] (a nontoxic cyanide source) allows in combination with 0.1 mol % Pd(OAc)2 a practical, ligand-free cyanation of aryl bromides in good to excellent yields.
S. A. Weissman, D. Zewge, C. Chen, J. Org. Chem., 2005, 70, 1508-1510.
A copper iodide mediated cyanation of arylboronic acids and aryl iodides with ethyl (ethoxymethylene)cyanoacetate as cyanating agent involves a C(sp2)-CN bond cleavage and tolerates a wide range of functional groups to provide the corresponding aryl nitriles in good yields.
C. Qi, X. Hu, H. He, Synlett, 2016, 27, 1979-1982.
A ZnO-supported palladium(0) nanoparticle catalyst has been applied for the efficient cyanation of a variety of functionalized aryl bromides and activated aryl chlorides with K4[Fe(CN)6] as benign cyanide source. This process circumvents the need for an additive and a ligand and offers high product yields, low catalyst loading (0.2 mol-% Pd), and recyclability of the catalyst.
T. Chatterjee, R. Dey, B. C. Ranu, J. Org. Chem., 2014, 79, 5875-5875.
A practical method for palladium-catalyzed cyanation of aryl halides using Pd/C can be applied to various aryl bromide and active aryl chloride substrates to effect efficient conversions. The process features many advantages over existing cyanation conditions and the practical utility of the process has been demonstrated on scale.
H. Yu, R. N. Richey, W. D. Miller, J. Xu, S. A. May, J. Org. Chem., 2011, 76, 665-668.
A palladium-catalyzed cyanation allows the conversion of highly challenging electron-rich aryl chlorides, in addition to electron-neutral and electron-deficient substrates, as well as nitrogen- and sulfur-containing heteroaryl chlorides under relatively mild conditions in the presence of sterically demanding, electron-rich phosphines as ligands.
A. Littke, M. Soumeillant, R. F. Kaltenbach III, R. J. Cherney, C. M. Tarby, S. Kiau, Org. Lett., 2007, 9, 1711-1714.
An efficient, mild, and inexpensive copper-catalyzed domino halogen exchange-cyanation procedure for aryl bromides was developed. The new method represents a significant improvement over the traditional Rosenmund-von Braun reaction: the use of catalytic amounts of copper and an apolar solvent greatly simplifies the isolation and purification. In addition, the new method exhibits excellent functional group compatibility.
J. Zanon, A. Klapars, S. L. Buchwald, J. Am. Chem. Soc., 2003, 125, 2890-2891.
Cyanation of aryl chlorides with potassium hexacyanoferrate(II) catalyzed by a cyclopalladated ferrocenylimine tricyclohexylphosphine complex is applicable to both activated and deactivated aryl chlorides. The corresponding aryl nitriles were isolated in good yields.
Y.-n. Cheng, Z. Duan, T. Li, Y. Wu, Synlett, 2007, 543-546.
A nickel-based catalytic system consisting of a unique diphosphine ligand such as dcype or dcypt enables the cyanation of versatile phenol derivatives such as aryl carbamates and aryl pivalates with aminoacetonitriles as metal-free cyanating agents This method is environmentally benign and easy-to-use.
R. Takise, K. Itami, J. Yamaguchi, Org. Lett., 2016, 18, 4428-4431.