496845-08-0Relevant academic research and scientific papers
Asymmetric cyclization of ω-formyl-1,3-dienes catalyzed by a zerovalent nickel complex in the presence of silanes
Sato, Yoshihiro,Saito, Nozomi,Mori, Miwako
, p. 9310 - 9317 (2002)
A nickel(0)-catalyzed asymmetric cyclization of ω-formyl-1,3-diene in the presence of silanes in which five- or six-membered carbocycles or pyrrolidine derivatives were afforded up to 86% ee by the use of (2R,5R)-2,5-dimethyl-l-phenylphospholane as a monodentate chiral ligand was investigated. The reaction course of this asymmetric cyclization can be explained for by two possible mechanisms: one in which the cyclization proceeds via a π-allylnickel intermediate to produce a cyclized product having an internal olefin in the side chain, and one in which the cyclization proceeds via a σ bond metathesis of silane and the nickel-oxygen bond of oxanickelacycle to produce a cyclized compound having a terminal olefin and/or an internal olefin in the side chain. It was speculated that both of these mechanisms operate in this asymmetric cyclization depending upon the nature of silanes and the reaction conditions.
