tert-Butyl nitrite (TBN)
The use of tert-butyl nitrite as the co-catalyst in a 2-azaadamantane-N-oxyl (AZADO)- and 9-azanoradamantane-N-oxyl (nor-AZADO)-catalyzed efficient aerobic oxidation of primary alcohols in MeCN instead of the previously reported AcOH provides the corresponding aldehydes selectively. The addition of saturated aqueous NaHCO3 after the completion of the reaction suppresses the overoxidation of the product during the workup.
M. Shibuya, K. Furukawa, Y. Yamamoto, Synlett, 2017, 28, 1554-1557.
A selective C-C bond cleavage of 1,3-diketones affords 1,2-diketones in high yields under mild reaction conditions in air by the use of FeCl3 as the catalyst and tert-butyl nitrite (TBN) as the oxidant without the use of solvent. The possible reaction mechanism is discussed. This protocol provides an expeditious route to useful 1,2-diketones.
L. Huang, K. Cheng, B. Yao, Y. Xie, Y. Zhang, J. Org. Chem., 2011, 76, 5732-5737.
The synthesis of aromatic azides from the corresponding amines is accomplished under mild conditions with tert-butyl nitrite and azidotrimethylsilane. 1,4-Disubstituted 1,2,3-triazoles were obtained in excellent yields from various aromatic amines without the need for isolation of the azide intermediates.
K. Barral, A. D. Moorhouse, J. E. Moses, Org. Lett., 2007, 9, 1809-1811.
Aliphatic and aromatic aldehydes gave acyl azides by reaction with iodine azide at 0 - 25°C. If the reaction is performed at reflux Curtius rearrangement occurs and carbamoyl azides are obtained directly from the aldehyde in 70-97% yield.
L. Marinescu, J. Thinggaard, I. B. Thomsen, M. Bols, J. Org. Chem., 2003, 68, 9453-9455.
A wide range of olefins with diverse functionalities has been nitrated in synthetically useful yields in a single step under metal-free conditions. This transformation is operationally simple and exhibits excellent E-selectivity. Furthermore, site selective nitration in a complex setup makes this method advantageous.
S. Maity, T. Naveen, U. Sharma, D. Maiti, Org. Lett., 2013, 15, 3384-3387.
A metal-free C≡C bond cleavage of terminal alkynes in the presence of tBuONO as a powerful nitrogenating agent provides a vast range of nitriles containing aryl, heteroaryl, and natural product derivatives.
U. Dutta, D. W. Lupton, D. Maiti, Org. Lett., 2016, 18, 860-863.
In situ nitrosation of anilines followed by reduction with ascorbic acid to form aryl radicals and thiolation with disulfides provided aryl sulfides. This mild, metal-free synthesis of aryl sulfides proceeded smoothly without heating or irradiation. This strategy can be expanded to the synthesis of aryl selenides.
M.-j. Bu, G.-p. Lu, C. Cai, Synlett, 2015, 26, 1841-1846.
tert-Butyl nitrite (TBN) is a multitask reagent for the controlled synthesis of N-nitrosoamides from N-alkyl amides, hydrolysis of N-methoxyamides to carboxylic acids, metal-free benzocoumarin synthesis from ortho-aryl-N-methoxyamides, and Ru-catalyzed isocoumarin synthesis.
S. L. Yedage, B. M. Bhanage, J. Org. Chem., 2017, 82, 5769-5781.
An unprecedented cross-coupling reaction between copper carbenes and nitroso radicals provides various isoxazolines via construction of C-C, C-O, and C=N bonds in a one-pot process. The convenient method offers mild reaction conditions and wide substrate scope.
R. Chen, Y. Zhao, S. Fang, W. Long, H. Sun, X. Wan, Org. Lett., 2017, 19, 5896-5899.
The combination of gold catalysis and radical chemistry enables the synthesis of 5-oxazole ketones from internal N-propargylamides in the presence of 4-MeO-TEMPO as an oxidant. The desired 5-oxazole ketones were provided in good yields with an excellent functional group compatibility under mild conditions.
H. An, S. Mai, Q. Xuan, Y. Zhou, Q. Song, J. Org. Chem., 2019, 84, 401-408.
A one-pot protocol for the construction of fluoroalkylated isoxazoles directly from commercially available amines and alkynes is regioselective, scalable, operationally simple, mild, and tolerant of a broad range of functional groups. Preliminary mechanistic investigations reveal that the transformation involves an unprecedented Cu-catalyzed cascade sequence involving RfCHN2.
X.-W. Zhang, W.-L. Hu, S. Chen, X.-G. Hu, Org. Lett., 2018, 20, 860-863.
tert-Butyl nitrite promotes an oxidative metal-free intermolecular sulfonamination of alkynylamines with sulfinic acids to provide substituted sulfonyl pyrroles via tandem addition/cyclization. Various substituted sulfonyl pyrroles are formed in good yields.
Z. Qi, Y. Jiang, Y. Wang, R. Yan, J. Org. Chem., 2018, 83, 8607-8614.
A convenient oxidation of oxindoles with molecular oxygen in the presence of tert-butyl nitrite as an additive enables a mild and metal-free synthesis of isatins without the need for any catalyst or base.
W.-T. Wei, W.-W. Ying, W.-M. Zhu, Y. Wu, Y.-L. Huang, Y.-Q. Cao, Y.-N. Wang, H. Liang, Synlett, 2017, 28, 2307-2310.
A tandem nitrosation/cyclization reaction of N-aryl cyanoacetamides with tert-butyl nitrite provides quinoxalin-2-ones in good yields with good functional group tolerance. The dehydrogenative N-incorporation is achieved through a sequence of nitrosation, tautomerization, and cyclization.
F. Wang, B.-L. Hu, L. Liu, H.-Y. Tu, X.-G. Zhang, J. Org. Chem., 2017, 82, 11247-11252.