Copper catalyzed reactions transfer radical cyclization

Greening of Copper Catalyzed Atom Transfer Radical Addition (ATRA) and Cyclization (ATRC) Reactions... 

Eckenhoff WT, Pintauer T. Copper catalyzed atom transfer radical addition (ATRA) and cyclization (ATRC) reactions in the presence of reducing agents. Catal. Rev. 2010 52 (l) l-59. 

Yang D, Yan Y, Zheng B, Gao Q, Zhu N. Copper(I)-catalyzed chlorine atom transfer radical cyclization reactions of unsaturated a-chloro p-keto esters. Org. Lett. 2006 8 (25) 5757-5760. 

Several examples of intramolecular addition of (5-unsaturated sulfonyl radicals have also been reported [36], In agreement with Baldwin s rule and notwithstanding the reversibility of the cyclization step, the 5-exo mode is preferred when the reaction is catalyzed by copper salts, since in this case the carbon-centered radical is trapped through a fast atom transfer reaction [36b],... 

---