Abstract:
Atom transfer radical addition (ATRA) and cyclization (ATRC) has been recognized as one of the most worthwhile reactions for carbon-carbon bond formation in organic chemistry. In order to develop an active catalyst for this reaction under visible light, ligands analogous to tris(pyridin-2-ylmethyl)amine (TPMA) were designed, synthesized and characterized (compound 1-4). Their copper complexes were studied in the photocatalyzed ATRA between styrene and carbon tetrachloride or chloroform under irradiation of white light (CFL 32 W) in the presence of azobisisobutyronitrile (AIBN) as a reducing agent. For carbon tetrachloride addition, high yields of styrene adduct was observed with over 80% yield at 8 h when TPMA, 1, 2 and 4 were used as the ligands. For a less active alkyl halide, chloroform, only ligand 1 gave over 80% yield of the styrene adduct after 24 h.
