摘要

Conjugate addition of Me3SiCN 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.

  • 出版日期2009-1-15