Efficient Epoxidation of Electron-Deficient Olefins with a Cationic Manganese Complex
Andrew Murphy, Geraud Dubois and T. D. P. Stack*
*Department of Chemistry, Stanford University, Stanford, California 94305, Email:
stackstanford.edu
A. Murphy, G. Dubois, T. D. P. Stack, J. Am. Chem. Soc., 2003, 125, 5250-5251.
DOI: 10.1021/ja029962r
Abstract
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.
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Details
The document discusses the development of a highly efficient and selective manganese complex, [MnII-(R,R-mcp)]2+, for the rapid epoxidation of terminal and electron-deficient olefins at room temperature. This complex uses commercially available peracetic acid as an oxidant and operates with low catalyst loadings, achieving high yields (>85%) and rapid reaction times (<5 minutes). The manganese complex is more stable and effective compared to its iron analogues, which suffer from higher catalyst loadings and capricious selectivity. The study highlights the complex's ability to epoxidize a wide range of olefins, including electron-rich and electron-poor substrates, with minimal solvent and scalable reactions from 5 mg to 25 g. The research also indicates that the active oxidant is likely a higher-valent manganese species, and the system shows potential for operational simplicity and broad substrate scope. Mechanistic studies and comparative analyses with iron analogues are ongoing to further understand and improve the catalyst's performance. The work is supported by the National Institutes of Health and includes detailed experimental procedures and crystallographic data available online.
Key Words
Epoxidation, Peracetic Acid, Manganese
Manganese(II)/Picolinic Acid Catalyst System for Epoxidation of Olefins
R. A. Moretti, J. Du Bois, T. D. P. Stack, Org. Lett., 2016, 18, 2528-2531.
Ligand and pH Influence on Manganese-Mediated Peracetic Acid Epoxidation of Terminal Olefins
A. J. Murphy, A. Pace, T. D. P. Stack., Org. Lett., 2004, 6, 3119-3122.
DOI: 10.1021/ol048846l
ID: J48-Y2003-1460