Synthesis of alkyl azides
A practical, rapid, and efficient microwave (MW) promoted nucleophilic substitution of alkyl halides or tosylates with alkali azides, thiocyanates or sulfinates in aqueous media tolerates various reactive functional groups.
Y. Ju, D. Kumar, R. S. Varma, J. Org. Chem., 2006, 71, 6697-6700.
Azide transfer of 2-azido-1,3-dimethylimidazolinium hexafluorophosphate (ADMP) to alcohols proceeds to give the corresponding azides under mild reaction conditions. The organic azides were easily isolated because the byproducts are highly soluble in water.
M. Kitamura, T. Koga, M. Yano, T. Okauchi, Synlett, 2012, 23, 1335-1338.
Bis(2,4-dichlorophenyl) phosphate mediates an efficient one-pot preparation of alkyl azides from alkanols in the presence of 4-(dimethylamino)pyridine as a base. Phosphorylpyridinium azide is believed to be the activating agent under these conditions.
C. Yu, B. Liu, L. Hu, Org. Lett., 2000, 2, 1959-1961.
A cocatalytic effect of nitro compounds enables a B(C6F5)3·H2O catalyzed azidation of tertiary aliphatic alcohols with a broad range of substrates. Kinetic, electronic, and spectroscopic evidence suggests that higher order hydrogen-bonded aggregates of nitro compounds and acids are the kinetically competent Brønsted acid catalysts.
M. Dryzhakov, M. Hellal, E. Wolf, F. C. Falk, J. Moran, J. Am. Chem. Soc., 2015, 137, 9555-9558.
A direct intermolecular anti-Markovnikov hydroazidation method for unactivated olefins is promoted by a catalytic amount of bench-stable benziodoxole at ambient temperature. This method facilitates previously difficult, direct addition of hydrazoic acid across a wide variety of unactivated olefins.
H. Li, S.-J. Shen, C.-L. Zhu, H. Xu, J. Am. Chem. Soc., 2019, 141, 9415-9421.
With AgNO3 as the catalyst and K2S2O8 as the oxidant, an efficient and general method for the decarboxylative azidation of aliphatic carboxylic acids with tosyl azide or pyridine-3-sulfonyl azide in aqueous MeCN solution afforded the corresponding alkyl azides under mild conditions. A broad substrate scope and wide functional group compatibility were observed. A radical mechanism is proposed.
C. Liu, X. Wang, Z. Li, L. Cui, C. Li, J. Am. Chem. Soc., 2015, 137, 9820-9823.
In a catalytic decarboxylative nitrogenation, a series of tertiary, secondary, and primary organoazides were prepared from easily available aliphatic carboxylic acids by using K2S2O8 as the oxidant and PhSO2N3 as the nitrogen source via an alkyl radical process.
Y. Zhu, X. Liu, X. Wang, X. Huang, T. Shen, Y. Zhang, X. Sun, M. Zou, S. Song, N. Jiao, Org. Lett., 2015, 17, 4702-4705.
A cobalt-catalyzed hydroazidation of α,α-disubstituted olefins with commercially available azide sources provides tertiary azides in useful yields and tolerates a variety of functional groups.
B. Gaspar, J. Waser, E. M. Carreira, Synthesis, 2007, 3839-3845.
A highly Marknovikov selectiv conversion of various olefins to azides was achieved using a cobalt catalyst, 3 equiv of TsN3 as nitrogen source and simple silanes (PhSiH3, TMDSO).
J. Waser, H. Nambu, E. M. Carreira, J. Am. Chem. Soc., 2005, 127, 8294-8295.
An organic acridinium salt catalyzes an anti-Markovnikov hydroazidation of activated olefins under irradiation from blue LEDs. This method is applicable to a variety of substituted styrenes and several vinyl ethers, yielding synthetically versatile hydroazidation products in excellent yield, whereas terminal styrenes provide hydroazidation products in moderate yields.
N. P. R. Onuska, M. E. Schutzbach-Horton, J. L. R. Collazo, D. A. Nicewicz, Synlett, 2020, 31, 55-59.
The combination of sodium periodate, potassium iodide, and sodium azide is an efficient, simple, and inexpensive reagent system for azidoiodination of alkenes. The regiospecific 1,2-azidoiodination proceeds in an anti-Markovnikov fashion to produce β-iodoazides in excellent yields.
P. V. Chouthaiwale, P. U. Karabal, G. Suryavanshi, A. Sudalai, Synthesis, 2010, 3879-3882.
A photoredox-catalyzed azidotrifluoromethylation of substituted styrenes as well as various activated and nonactivated alkenes using [Ru(bpy)3(PF6)2] as the photocatalyst and Umemoto’s reagent as the CF3 source delivers a wide range β-trifluoromethylated azides or amines in good yields.
G. Dagousset, A. Carboni, E. Magnier, G. Masson, Org. Lett., 2014, 16, 4340-4343.