An effective epoxidation of lipophilic alkenes using hydrogen peroxide was accomplished with a manganese sulfate/bicarbonate catalytic system in an ionic liquid at room temperature.
K.-H. Tong, K.-Y. Wong, T. H. Chan, Org. Lett., 2003, 5, 3423-3425.
An epoxidation of alkenes using hydrogen peroxide as the terminal oxidant is promoted by catalytic amounts (1.0-0.1 mol %) of manganese(2+) salts, and must be performed using at least catalytic amounts of bicarbonate buffer. Various aryl-substituted, cyclic, and trialkyl-substituted alkenes were epoxidized under these conditions using 10 equiv of hydrogen peroxide, but monoalkyl-alkenes were not. Additives such as sodium acetate and salicylic acid enhanced the rate of the desired epoxidation reaction by 2-3 times. Possible mechanisms for the reaction are discussed.
B. S. Lane, M. Vogt, V. J. DeRosa, K. Burgess, J. Am. Chem. Soc., 2002, 124, 11946-11954.
Readily available Mn(III) complexes catalyze alkene epoxidation by bleach in good yields. A highly enantioselective epoxidation catalyst was developed through a logical sequence of ligand modifications.
E. N. Jacobsen, W. Zhang, A. R. Muci, J. R. Ecker, L. Deng, J. Am. Chem. Soc., 1991, 113, 7063-7064.
The complex [MnII(R,R-mcp)(CF3SO3)2] is a very efficient and practical catalyst for the epoxidation of a wide scope of olefins including terminal, tertiary, cis and trans internal, enones, and methacrylates using peracetic acid as the terminal oxidant.
A. Murphy, G. Dubois, T. D. P. Stack, J. Am. Chem. Soc., 2003, 125, 5250-5251.
Reactions of vinyl azides with monocyclic cyclopropanols provided pyridines in the presence of Mn(acac)3, whereas those with bicyclic cyclopropanols led to the formation of 2-azabicyclo[3.3.1]non-2-en-1-ol derivatives using a catalytic amount of Mn(acac)3.
Y.-F. Wang, S. Chiba, J. Am. Chem. Soc., 2009, 131, 12570-12572.
Selective addition of radicals to isonitriles enables a general route for the preparation of N-heteroaromatics. This method utilizes alkenes as synthetic equivalents of alkynes by coupling homoallylic ring expansion to yield the formal 6-endo products with aromatization via stereoelectronically assisted C-C bond scission.
C. J. Evoniuk, G. dos Passos Gomes, M. Ly, F. D. White, I. V. Alabugin, J. Org. Chem., 2017, 82, 4265-4278.
An efficient rhodium-catalyzed C-H activation and multistep cascade reaction of benzimidates and alkenes enables the synthesis of diverse difunctionalized indenones in the presence of Mn(OAc)2. The transformation involves the cleavage and formation of multiple bonds in one pot under mild reaction conditions.
N. Lv, Z. Chen, Y. Liu, Z. Liu, Y. Zhang, Org. Lett., 2017, 19, 2588-2591.
Mn(OAc)3 based regioselective oxidation of various 2-cyclopentenone, 2-cyclohexenone and aromatic ketone derivatives in benzene afforded the corresponding tertiary α'-acetoxy oxidation products in good yields.
C. Tanyeli, C. Iyiguen, Tetrahedron, 2003, 59, 7135-7139.
A single electron oxidation of the commercially available CF3SO2Na (Langlois' reagent) using Mn(OAc)3·2H2O as the oxidant enables a simple and efficient method for hydrotrifluoromethylation of unactivated alkenes. The reaction proceeds readily under mild conditions and tolerates various functional groups.
B. Cui, H. Sun, Y. Xu, L. Li, L. Duan, Y.-M. Li, J. Org. Chem., 2018, 83, 6015-6024.
A Mn(OAc)3-promoted oxidative phosphonylation of N,N-dimethylenaminones with H-phosphonates provides functionalized β-ketophosphonates in very good yields under mild reaction conditions. This method offers operational simplicity, broad substrate scope, and large-scale preparation.
P. Zhou, B. Hu, L. Li, K. Rao, J. Yang, F. Yu, J. Org. Chem., 2017, 82, 13268-13276.
Mn(OAc)3-mediated phosphinoyl radical addition followed by CuCN-catalyzed cyanation enables a double-functionalization reaction of alkenes under mild conditions to afford vicinal cyanophosphinoylation products.
P.-Z. Zhang, L. Zhang, J.-A. Li, A. Shoberu, J.-P. Zou, W. Zhang, Org. Lett., 2017, 19, 5537-5540.
A Mn(III)-mediated radical cascade cyclization of o-alkenyl aromatic isocyanides with boronic acids provides N-unprotected 2-aryl-3-cyanoindoles. A possible mechanism involves a sequential intermolecular radical addition, intramolecular cyclization, and cleavage of a C-C bond under mild reaction conditions. Either H2O or O2 acts as the oxygen source for the elimination of benzaldehyde.
L. Liu, L. Li, X. Wang, R. Sun, M.-D. Zhou, H. Wang, Org. Lett., 2021, 23, 5826-5830.
Manganese triacetate mediates an oxidative C-4 arylation of 2-aryl-quinazoline 3-oxides with arylboronic acids to provide 2,4-diarylated quinazoline 3-oxides in very good yields. The method tolerates various substituents on both aromatic rings.
R. Samandram , M. Ç. Korukçu, N. Coşkun, Synthesis, 2022, 54, 210-216.