92356-40-6Relevant articles and documents
Ruthenium-lewis acid catalyzed asymmetric diels-alder reactions between dienes and α,β-unsaturated ketones
Rickerby, Jenny,Vallet, Martial,Bernardinelli, Gerald,Viton, Florian,Kuendig, E. Peter
, p. 3354 - 3368 (2008/03/27)
The complex [Ru(Cp)(R,R-BIPHOP-F)(acetone)][SbF6],(R,R)-1a. was used as catalyst for asymmetric Diels-Alder reactions between dienes (cyclopentadiene, methylcyclopentadienc, isoprene, 2,3-dimethylbutadiene) and α,β-unsaturated ketones (methyl vinyl ketone (MVK). ethyl vinyl ketone, divinyl ketone, α-bromovinyl methyl ketone and α-chlorovinyl methyl ketone). The cycloaddition products were obtained in yields of 50-_90% and with enantioselectivities up to 96% ee. Ethyl vinyl ketone, divinyl ketone and the halogenated vinyl ketones worked best and their reactions with acyclic dienes consistently provided products with >90% ee. α-Chlorovinyl methyl ketone performed better than α-bromovinyl methyl ketone. The reaction also provided a [4.3.1]bicyclic ring system in 95% ee through an intramolecular cycloaddition reaction. Crystal structure determinations of [Ru(Cp)((S,S)-BIPHOP-F)(mvk)]-[SbF6], (S,S)-1b, and [Ru(Cp)((R,R)-Me4BIPHOP-F)(acrolein)][SbF6], (R,R)-2b, provided the basis for a rationalization of the asymmetric induction.
