Quinone-Catalyzed Selective Oxidation of Organic Molecules

There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

Abstract

Quinones are common stoichiometric reagents in organic chemistry. High potential para-quinones, such as DDQ and chloranil, are widely used and typically promote hydride abstraction. In recent years, many catalytic applications of these methods have been achieved by using transition metals, electrochemistry or O 2 to regenerate the oxidized quinone in situ. Complementary studies have led to the development of a different class of quinones that resemble the ortho-quinone cofactors in Copper Amine Oxidases and mediate efficient and selective aerobic and/or electrochemical dehydrogenation of amines. The latter reactions typically proceed via electrophilic transamination and/or addition-elimination reaction mechanisms, rather than hydride abstraction pathways. The collective observations show that the quinone structure has a significant influence on the reaction mechanism and have important implications for the development of new quinone reagents and quinone-catalyzed transformations.

Related collections

Most cited references 298

Record: found
Abstract: found
Article: not found

Redox catalysis in organic electrosynthesis: basic principles and recent developments.

Robert Francke, R. Daniel Little (2014)

Electroorganic synthesis has become an established, useful, and environmentally benign alternative to classic organic synthesis for the oxidation or the reduction of organic compounds. In this context, the use of redox mediators to achieve indirect processes is attaining increased significance, since it offers many advantages compared to a direct electrolysis. Kinetic inhibitions that are associated with the electron transfer at the electrode/electrolyte interface, for example, can be eliminated and higher or totally different selectivity can be achieved. In many cases, a mediated electron transfer can occur against a potential gradient, meaning that lower potentials are needed, reducing the probability of undesired side-reactions. In addition, the use of electron transfer mediators can help to avoid electrode passivation resulting from polymer film formation on the electrode surface. Although the principle of indirect electrolysis was established many years ago, new, exciting and useful developments continue to be made. In recent years, several new types of redox mediators have been designed and examined, a process that can be accomplished more efficiently and purposefully using modern computational tools. New protocols including, the development of double mediatory systems in biphasic media, enantioselective mediation and heterogeneous electrocatalysis using immobilized mediators have been established. Furthermore, the understanding of mediated electron transfer reaction mechanisms has advanced. This review describes progress in the field of electroorganic synthesis and summarizes recent advances.

0 comments Cited 375 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: not found
Article: not found

Copper-Catalyzed Aerobic Oxidative CH Functionalizations: Trends and Mechanistic Insights

Alison E. Wendlandt, Alison Suess, Shannon S Stahl (2011)

0 comments Cited 254 times – based on 0 reviews      Review now

Bookmark

Record: found
Abstract: found
Article: not found

Chemoselective metal-free aerobic alcohol oxidation in lignin.

Alireza Rahimi, Ali Azarpira, Jie-Hoon Kim … (2013)

An efficient organocatalytic method for chemoselective aerobic oxidation of secondary benzylic alcohols within lignin model compounds has been identified. Extension to selective oxidation in natural lignins has also been demonstrated. The optimal catalyst system consists of 4-acetamido-TEMPO (5 mol %; TEMPO = 2,2,6,6-tetramethylpiperidine-N-oxyl) in combination with HNO3 and HCl (10 mol % each). Preliminary studies highlight the prospect of combining this method with a subsequent oxidation step to achieve C-C bond cleavage.