Regio- and enantioselectivity in the alkylation and etherification reactions of cinnamyl allylic derivatives catalyzed by [(η5-C5R5)Ru(N–N*)(NCCH3)]PF6 (R = H, Me) complexes containing N–N* bulky chiral ligands of different rigidity and flexibility
✍ Scribed by Maria Saporita; Giovanni Bottari; Giuseppe Bruno; Dario Drommi; Felice Faraone
- Publisher
- Elsevier Science
- Year
- 2009
- Tongue
- English
- Weight
- 206 KB
- Volume
- 309
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
a b s t r a c t [( 5 -C 5 R 5 )Ru(N-N*)(NCMe)]PF 6 (R = H, N-N* = (Sa)-1, 5; (Sa)-2, 6; (R,R)-3, 7; (R,R)-4; 8; R = Me, N-N* = (Sa)-1, 9) complexes containing N-N* bulky chiral ligands of different rigidity and flexibility were synthesized by reacting the precursor [( 5 -C 5 R 5 )Ru(NCMe) 3 ]PF 6 (R = H, Me) with the N-N* ligand in a 1:1 molar ratio. The more bulky ( 5 -C 5 Me 5 ) ligand gave low stability to the complexes [( 5 -C 5 Me 5 )Ru(N-N*)(NCMe)]PF 6 , when N-N* = (Sa)-2, (R,R)-3, (R,R)-4, in comparison to ( 5 -C 5 H 5 ) ligand and prevented their characterization. The catalytic activity of complexes 5-9 in allylic alkylation and etherifications reactions, using malonate and phenoxide anions as nucleophiles respectively, were investigated and compared to the results obtained with corresponding precursors [( 5 -C 5 H 5 )Ru(NCMe) 3 ]PF 6 and [( 5 -C 5 Me 5 )Ru(NCMe) 3 ]PF 6 . The effect of bulkiness and of rigidity and flexibility ligand features is discussed.