Fun with radicals: Some new perspectives for organic synthesis

Abstract

International audienceThe degenerative radical addition-transfer of xanthates onto alkenes allows the rapid assembly of richly functionalized structures. Various families of open-chain, cyclic, and polycyclic compounds can thus be readily accessed. Furthermore, the process can be extended to the synthesis or modification of aromatic and heteroaromatic derivatives by exploiting the possibility of using peroxides both as initiators and stoichiometric oxidants. The modification of existing polymers and the controlled synthesis of block polymers by what is now known as the RAFT/MADIX (reversible addition-fragmentation transfer/ macromolecular design by interchange of xanthate) process is described briefly. © 2010 IUPAC

Some aspects of radical cascade and relay reactions

“…This gap in synthesis has now been largely filled by a reaction we discovered some time ago. It is based on the degenerative xanthate transfer depicted in greatly simplified form in scheme 10 [30,31].…”

“…For a more detailed discussion of the mechanism, the reader is directed to [29,30]. For the purposes of the present overview, suffice it to say that the reaction of radical R• with its precursor 57 to give intermediate 58 ( …”

Living Radical Polymerization by the RAFT Process – A Third Update

“…include those on the kinetics and mechanism of RAFT polymerization, [26,27] RAFT agent design and synthesis, [28] the use of RAFT to probe the kinetics of radical polymerization, [29] microwaveassisted RAFT polymerization, [30,31] RAFT polymerization in microemulsion, [32] end-group removal/transformation, [33][34][35][36] the use of RAFT in organic synthesis, [37] the combined use of RAFT polymerization and click chemistry, [38] the synthesis of star polymers and other complex architectures, [39][40][41][42] the synergistic use of RAFT polymerization and ATRP, [43,44] the synthesis of self assembling and/or stimuli-responsive polymers, [45][46][47] and the use of RAFT-synthesized polymers in green chemistry, [48] polymer nanocomposites, [49][50][51] drug delivery and bioapplications, [41,46,47,[52][53][54][55][56][57][58][59][60] and applications in cosmetics [61] and optoelectronics. [62] The process is also given substantial coverage in most recent reviews that, in part, relate to polymer synthesis, living or controlled polymerization or novel architectures.…”

“…Single unit monomer insertion can also be favoured over polymerization by use of equimolar amounts of monomer and RAFT agent. Zard and co-workers have reviewed [37] and reported further applications [492,553] of the use of single unit insertion of non-activated monomers into xanthates in organic synthesis. For example, insertion of N-vinylphthalimide provides a synthetic route to amines.…”

RAFT Polymerization – Then and Now

“…The historical development of RAFT (reversible addition-fragmentation chain transfer) polymerization at CSIRO (1)(2)(3) and the parallel development of MADIX (macromolecular design via interchange of xanthates) at Rhodia (4,5) has been described in a number of recent reviews. The invention of RAFT at CSIRO should be seen against a background of research into defining and understanding polymer structures and on controlling the outcome of radical polymerization that had commenced more than two decades earlier.…”