Organic synthesis atom transfer radical addition

Carbon-carbon bond formation is a fundamental reaction in organic synthesis [1, 2,3,4], One way to form such a bond and, thus, extend a carbon chain is by the addition of a polyhalogenated alkane to an alkene to form a 1 1 adduct, as shown in Scheme 1. This reaction was first reported in the 1940s and today is known as the Kharasch addition or atom transfer radical addition (ATRA) [5,6], Historically, Kharasch addition reactions were conducted in the presence of radical initiators or... 

This catalytic sequence is known as Kharasch addition or atom transfer radical addition (ATRA) [4]. Various polyhalogenated compounds such as CCI4 and CCI3CO2R are used as the organic halides, and transition metal salts or complexes are used as the catalyst [3]. Intramolecular version of the Kharasch addition reaction (atom transfer radical cyclization, ATRC) has opened novel synthetic protocols to the synthesis of carbocyde or heterocyles catalyzed by transition metals [5-7], and this has become a very important field in free radical cydization in organic synthesis. Transition metal-catalyzed Kharasch reactions sometimes afford telomers or poly-... 

Atom transfer radical polymerization (ATRP) is based on the well-established method of carbon-carbon bond formation by atom transfer radical addition used in organic synthesis. 

ATRP is an extension of atom transfer radical addition (ATRA), which is a well-known method of carbon-carbon bond formation (catalyzed by transition metal complexes) in organic synthesis. ATRP also has roots in the transition metal catalyzed telomerization reactions (Boutevin,... 

Radical cyclizations of this type can be also achieved in chemical radical chain reactions [124, 125], often in a wider scope. The anodically initiated cyclization, however, has advantages. It avoids tin hydride, which is mostly used as coreagent in chemical radical chain cyclizations and because the toxicity of tin organics makes these reactions less attractive for the synthesis of pharmaceuticals. In chemical radical chain reactions, which involve in most cases an addition and an atom-transfer reaction, one C,C- and one C,H- or C,X bond is being formed, while in anodic addition followed by heterocoupling two C,C bonds are being formed, where the second one is established simply and in wide variety by the appropriate choice of the coacid. 

The addition of a single-bonded reagent across a multiple bond is one of the fundamental reactions of organic radicals. The basic principles of this reaction were first advanced by Kharasch in pioneering studies on the mechanism of the peroxide-initiated anti-Maikovnikov addition of hydrogen bromide to alkenes.1 In the atom transfer method, the generation and removal of radicals are coupled and occur in the key atom transfer step. Compared to other methods, the atom transfer method provides unique options for synthetic reactions. But there are also important limitations. Recently, there has been a renewed interest in the application of the characteristics of atom transfer reactions in synthesis and new developments have been reviewed.5,161... 

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