Copper catalyzed atom transfer radical cascade reactions in the presence of free-radical diazo initiators as reducing agentsf

摘要

Exceptional activity of [Cu~Ⅱ(TPMA)Cl][Cl] (TPMA = tris(2-pyridylmethyl)amine) complex in atom transfer radical addition (ATRA) of CCl_4 to 1,6-dienes followed by sequential atom transfer radical cyclization (ATRC) in the presence of free-radical diazo initiators as reducing agents is reported.rnThe formation of carbon-carbon bonds using atom transfer radical addition (ATRA) is becoming an increasingly popular synthetic tool. Transition metal complexes of Cu, Ru, Fe, and Ni are typically used as catalysts for such transformations. Until recently, the major drawback of this useful synthetic method remained the large amount of catalyst required to achieve high selectivity towards the desired target compound (as high as 30 mol% relative to alkene). This obstacle caused serious problems in product separation and catalyst regeneration, making the process environmentally unfriendly and expensive.