3-Chloroperoxybenzoic acid, MCPBA, meta-Chloroperbenzoic acid
MCPBA is a strong oxidizing agent, which is comparable with other peracids. Advantages of 3-chloroperbenzoic acid is its handling, because it is present as powder, which can be kept in the refrigerator. Nevertheless, material of purity >75% is rarely available commercially, since the pure compound is not particularly stable. Therefore the transport in airplanes with a content of > 72% is forbidden. Main pollution is 3-chlorobenzoic acid (10%) as well as for safety reasons water.
MCPBA is versatile applicable as peracid for use in laboratories.
Main areas are the oxidation of
- aldehydes and ketones to esters (Bayer-Villiger-Oxidation)
- olefines to epoxides
- sulfides to sulfoxides and sulfones
- amines to nitroalkanes, nitroxides or N-oxides
However, for reasons of the atomic economy, the use of MCPBA in production should be avoided. The research concentrates within this area rather on the use of hydrogen peroxide in connection with suitable catalysts or in situ generated, simpler peracids, such as peracetic acid or on potassium peroxymonosulfate (Oxone). In many reactions MCPBA with an outstanding reactivity is however more selective than hydrogen peroxide and other peracids.
Use of a solvent with greater density than the fluorous phase is an alternative to the U-tube method in phase-vanishing reactions in cases where both reactants are less dense than the fluorous phase.
N. K. Jana, J. G. Verkade, Org. Lett., 2003, 5, 3787-3790.
The results of a highly diastereoselective epoxidation of allylic diols derived from Baylis-Hillman adducts are reported.
R. S. Porto, M. L. A. A. Vasconcellos, E. Ventura, F. Coelho, Synthesis, 2005, 2297-2306.
A clean and efficient and metal-free diacetoxylation reaction of alkenes using commercially available peroxyacids as the oxidants is catalyzed by triflic acid. This method enables also oxidative lactonizations of unsaturated carboxylic acids in good to high yields.
Y.-B. Kang, L. H. Gade, J. Org. Chem., 2012, 77, 1610-1615.
Sequential treatment of a 1,2-disubstituted olefin with m-CPBA, Br3CCO2H, and DBU results in the one-pot, stereospecific conversion of the olefin to the corresponding disubstituted cyclic carbonate. When a solution of a secondary allylic or homoallylic amine and Br3CCO2H is sequentially treated with m-CPBA then DBU, the product of the reaction is a cyclic carbamate.
S. G. Davies, A. M. Fletcher, W. Kurosawa, J. A. Lee, G. Poce, P. M. Roberts, J. E. Thomson, D. M. Williamson, J. Org. Chem., 2010, 75, 7745-7756.
Several amides were obtained in high yields by an efficient method from the corresponding imines which are readily prepared from aldehydes. This procedure involves the oxidation of aldimines with m-CPBA and BF3·OEt2. In this reaction, the product is strongly influenced by the electron releasing capacity of the aromatic substituent (Ar).
G. An, M. Kim, J. Y. Kim, H. Rhee, Tetrahedron Lett., 2003, 44, 2183-2186.
Various ketones could be reacted into α-tosyloxy ketones in the presence of MCPBA, PTSA•H2O, catalytic amounts of iodine and tert-butylbenzene in a mixture of acetonitrile and 2,2,2-trifluoroethanol. In the reaction, 4-tert-butyl-1-iodobenzene is formed at first and then converted into the α-tosyloxylation reagent 4-tert-butyl-1-[(hydroxy)(tosyloxy)iodo]benzene by the reaction with MCPBA and PTSA•H2O.
A. Tanaka, K. Moriyama, H. Togo, Synlett, 2011, 1853-1854.
Various α-tosyloxyketones were efficiently prepared in high yields from the reaction of ketones with m-chloroperbenzoic acid and p-toluenesulfonic acid in the presence of a catalytic amount of iodobenzene.
Y. Yamamoto, H. Togo, Synlett, 2006, 798-800.
Reaction of methyl sulfinates with lithium amides followed oxidation of the resulting sulfinamides provides primary, secondary, and tertiary alkane-, arene- and heteroarenesulfonamides in high yields. This protocol avoids the use of hazardous, unstable, or volatile reagents and does not affect the configurational stability of the amines.
J. L. C. Ruano, A. Parra, F. Yuste, V. M. Mastranzo, Synthesis, 2008, 311-312.
β-Piperidinoethylsulfides can be oxidized by m-chloroperbenzoic acid to intermediates containing both N-oxide and sulfone functions. These undergo a Cope-type elimination to a vinylsulfone that can be captured by amines to afford β-aminoethylsulfones. The synthetic methodology developed can be utilized in multiple-parallel format and has numerous potential applications in medicinal chemistry.
R. J. Gruffin, A. Henderson, N. J. Curtin, A. Echalier, J. A. Endicott, I. R. Hardcastle, D. R. Newell, M. E. M. Noble, L.-Z. Wang, B. T. Golding, J. Am. Chem. Soc., 2006, 128, 6012-6013.
The synthesis of N-cyanosulfilimines can readily be achieved by reaction of the corresponding sulfides with cyanogen amine in the presence of a base and NBS or I2 as halogenating agents. Oxidation followed by decyanation affords synthetically useful sulfoximines.
O. García Mancheño, O. Bistri, C. Bolm, Org. Lett., 2007, 9, 3809-3811.
Iodobenzene can be used as a recyclable catalyst in combination with m-chloroperbenzoic acid as the terminal oxidant for an efficient and regioselective monobromination of electron-rich aromatic compounds. The bromination of electron-rich aromatic compounds with lithium bromide was fast in tetrahydrofuran at room temperature, providing regioselective monobrominated products in good yields.
Z. Zhou, X. He, Synthesis, 2011, 207-209.
A new, regiospecific, sequential one-pot synthesis of symmetrical and unsymmetrical diaryliodonium tetrafluoroborates, which are the most popular salts in metal-catalyzed arylations, is fast and high-yielding and has a large substrate scope. Furthermore, the corresponding diaryliodonium triflates can conveniently be obtained via an in situ anion exchange.
M. Bielawski, D. Aili, B. Olofsson, J. Org. Chem., 2008, 73, 4602-4607.
One-pot syntheses of neutral and electron-rich [hydroxy(tosyloxy)iodo]arenes (HTIBs) from iodine and arenes avoid the need for expensive iodine(III) precursors. A large set of HTIBs, including a polyfluorinated analogue, can be obtained from the corresponding aryl iodides under mild conditions, without excess reagents, in high yields.
E. A. Merritt, V. M. T. Carneiro, L. F. Silva Jr., B. Olofsson, J. Org. Chem., 2010, 75, 7416-7419.
A direct synthesis of symmetric and unsymmetric electron-rich diaryliodonium salts delivers diaryliodonium tosylates in high yields using MCPBA and toluenesulfonic acid. An in situ anion exchange has also been developed, giving access to the corresponding triflate salts.
M. Zhu, N. Jalalian, B. Olofsson, Synlett, 2008, 592-596.