Synthesis of benzyl azides
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 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.
The use of copper-catalyzed visible light photochemistry and the Zhdankin azidoiodinane reagent enables an azidation method for C-N bond formation at benzylic C-H positions via a radical chain reaction. The method is applicable to a wide range of substrates bearing different functional groups and having a primary, secondary, or tertiary benzylic position.
P. T. G. Rabet, G. Fumagalli, S. Boyd, M. F. Greaney, Org. Lett., 2016, 18, 1645-1649.
A bismuth(III)-catalyzed direct azidation of sec-benzyl alcohols provided sec-benzyl azides in good yield within a short reaction time.
J. Tummatorn, C. Thongsornkleeb, S. Ruchirawat, P. Thongaram, B. Kaewmee, Synthesis, 2015, 47, 323-329.
The use of azidotrimethylsilane (TMSN3) as azide source in the presence of copper(II) triflate [Cu(OTf)2] enables a simple, practical, and efficient direct synthesis of organic azides in good yields from secondary benzylic alcohols.
P. Khedar, K. Pericherla, A. Kumar, Synlett, 2014, 25, 515-518.
The sensitive azidocarbenium ion intermediate can be trapped with various nucleophiles to provide azides in excellent chemoselectivity. The method enables the chemoselective synthesis of primary and secondary benzyl azides from aldehydes in a one-pot reaction.
S. Pramanik, P. Ghorai, Org. Lett., 2014, 16, 2104-2107.
A catalytic amount of iron trichloride enables C-C and C-N bond formation reactions of O-heterocycles accompanied by ring opening in the presence of TMSN3 or allylsilanes. The reactions smoothly proceeded at room temperature to give the corresponding primary saturated alcohols from 2-substituted tetrahydrofurans, ortho-substituted benzyl alcohols from phthalanes, and saturated carboxylic acids from lactones in high yields.
Y. Sawama, K. Shibata, Y. Sawama, M. Takubo, Y. Monguchi, N. Krause, H. Sajiki, Org. Lett., 2013, 15, 5282-5285.
An operationally simple iron-catalyzed difunctionalization of alkenes provides primary 2-azidoamines, which are versatile precursors to vicinal diamines. A wide array of alkene substrates are tolerated, including complex drug-like molecules and a tripeptide. Facile, chemoselective derivatizations of the azidoamine group demonstrate the versatility of this masked diamine motif.
S. Makai, E. Falk, B. Morandi, J. Am. Chem. Soc., 2020, 142, 21548-21555.
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.
Trifluoromethylsulfonyl-pyridinium salt (TFSP) is an efficient, solid trifluoromethylation reagent, which can be readily prepared from cheap and easily available bulk industrial feedstocks. TFSP can generate a trifluoromethyl radical under photocatalysis, that can be used for azido- or cyano-trifluoromethylation reactions of alkenes.
M. Zhang, J.-H. Lin, J.-C. Xiao, Org. Lett., 2021, 23, 6079-6083.
A metal-free azide insertion of α-aryl α-diazoesters in the presence of B(C6F5)3 as catalyst affords the corresponding products in good yields. The reaction offers easy operation, wide substrate scope, and mild conditions and tolerates alkene and alkyne functional groups without cyclopropanation or cyclopropenation side products. A one-pot synthesis of 1,2,3-triazoles is also described.
H. H. San, C.-Y. Wang, H.-P. Zeng, S.-T. Fu, M. Jiang, X.-Y. Tang, J. Org. Chem., 2019, 84, 4478-4485.