title: Ni(0)-catalyzed conjugate addition of Me3SiCN to ynones: alpha-bromo-beta-cyano tetrasubstituted enones.
abstract: Conjugate addition of Me(3)SiCN to ynones is smoothly catalyzed by Ni(cod)(2) to give the beta-cyanosilyloxyallene quantitatively. Further reaction of the silyloxyallenes with NBS provides the tetrasubstituted alpha-bromo-beta-cyano enones in high yields (up to 95%) with excellent Z-selectivity (E/Z = up to >1/99). X-ray crystallographic analysis showed a bent structure of the alpha-bromo-beta-cyano enone due to a deconjugation of the pi-bond and carbonyl group.
authors.affiliation: Department of Chemistry, Graduate School of Science, Chiba University, Inage 1-33, Chiba 263-8522, Japan. tarai@faculty.chiba-u.jp
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Arai
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Suemitsu
authors.forename: Yui
authors.initials: Y
authors.lastname: Ikematsu