New Generation Method for a Samarium(II) Equivalent: Me3SiX (X = Br and I)/Sm-Assisted Intermolecular Carbon-Carbon Bond Forming Reactions of Carbonyl Compounds
作者:Noriyuki Akane、Tadashi Hatano、Hiroko Kusui、Yutaka Nishiyama、Yasutaka Ishii
DOI:10.1021/jo00104a056
日期:1994.12
Samarium(II) species can be efficiently generated in situ from a reaction between elemental samarium and chlorotrimethylsilane (Me(3)SiCl)/sodium iodide (NaI) reagent or bromotrimethylsilane (Me(3)SiBr) in acetonitrile. The reductive coupling reaction of carbonyl compounds was achieved by the action of Sm(II) reagent thus generated from Sm/Me(3)SiCl/NaI or Sm/Me(3)SiBr to give the corresponding pinacol products in moderate to high yields. The samarium(II) reagent induced the intermolecular coupling reaction of alpha,beta-unsaturated esters with carbonyl compounds or imines followed by intramolecular cyclization to form the corresponding gamma-lactones or gamma-lactams in moderate yields. The reaction of alpha-bromo esters with carbonyl compounds using the Sm (II) species, generated from the Sm/Me(3)SiX system, led to the corresponding beta-hydroxy esters in 52-95% yields.