Categories: C-I Bond Formation >
Synthesis of benzyl iodides
The use of a CeCl3·7H2O/NaI system in acetonitrile enables an exceedingly mild preparation of iodides from alcohols. The simplicity of this approach, the low cost of reagents, and the ease of use display the attractiveness of the present method for a wide variety of alcohols.
M. Di Deo, E. Marcantoni, E. Torregiani, G. Bartoli, M. C. Bellucci, M. Bosco, L. Sambri, J. Org. Chem., 2000, 65, 2830-2833.
Silicaphosphine (Silphos), [P(Cl)3−n(SiO2)n] is a new heterogeneous reagent that converts alcohols and thiols to their corresponding bromides and iodides in the presence of molecular halogen in refluxing CH3CN in high to quantitative yields. Separation of the Silphos oxide byproduct can be achieved by a simple filtration.
N. Iranpoor, H. Firouzabadi, A. Jamalian, F. Kazemi, Tetrahedron, 2005, 61, 5699-5704.
The combination of Ph3P and easily available 1,2-dihaloethanes (XCH2CH2X; X = Cl, Br, or I), was very effective for a mild deoxygenative halogenation of alcohols and aldehydes. The use of (EtO)3P instead of Ph3P enables a convenient purification process, as the byproduct (EtO)3P═O could be removed by aqueous washing. A dehydroxy-fluorination proceeds well in the presence of ICH2CH2I and CsF as fluoride source in DMF.
J. Chen, J.-H. Lin, J.-C. Xiao, Org. Lett., 2018, 20, 3061-3064.
The use of H3PO3/I2 enables a reductive iodination of various aromatic aldehydes to produce benzyl iodides. The benzyl iodides can be converted into diarylmethanes or cyclic compounds in good yields via in situ Friedel-Crafts type reactions.
F. Lv, J. Xiao, J. Xiang, F. Guo, Z.-L. Tang, L.-B. Han, J. Org. Chem., 2021, 86, 3081-3088.
Anhydrous hydrogen iodide preparated directly from molecular hydrogen and iodine using a rhodium catalyst is highly active in the transformations of alkenes, phenyl aldehydes, alcohols, and cyclic ethers to the corresponding iodoalkanes. Therefore, the present methodology offers a practical method for the preparation of various iodoalkanes in excellent atom economy.
C. Zeng, G. Shen, F. Yang, J. Chen, X. Zhang, C. Gu, Y. Zhou, B. Fan, Org. Lett., 2018, 20, 6859-6862.