Categories: C-Br Bond Formation >
Synthesis of β-Bromoketones
A simple electrochemical protocol for the preparation of 2-bromoethyl- and 2-iodoethyl ketones from cyclopropanols and magnesium halides proceeds with exclusive regioselectivity and without epimerization of the α-stereocenter in the products. 2-bromoethyl ketones undergo smooth copper and nickel-catalyzed alkylation, alkenylation, and arylations reactions.
M. V. Barysevich, Y. M. Aniskevich, A. L. Hurski, Synlett, 2021, 32, 1934-1938.
A mild oxidation of selected anions (N3-, SCN-, I-, and Br-) by ceric ammonium nitrate (CAN) in the presence of substituted cyclopropyl alcohols provides β-functionalized ketones in short reaction times. This method provides an alternative pathway to important starting materials and intermediates in organic synthesis.
J. Jiao, L. X. Nguyen, D. R. Patterson, R. A. Flowers II, Org. Lett., 2007, 9, 1323-1326.
Treatment of vinyl ketones with a combination of TiCl4 and n-Bu4NI followed by an addition of a variety of aldehydes provides syn-α-iodomethyl-β-hydroxy ketones with high stereoselectivity. The use of n-Bu4NBr or n-Bu4NCl provides the corresponding bromo or chloro compounds in good yields.
Z. Han, S. Uehira, H. Shinokubo, K. Oshima, J. Org. Chem., 2001, 66, 7854-7857.