Catalytic Isomerization of Allylic Alcohols by (η6-p-Cymene)- Ruthenium(II) Complexes in Organic and Aqueous Media: New Recyclable and Highly Efficient Catalysts in Water Containing Ammonium-Functionalized Ligands

The water-soluble complexes [RuCl 2 (η 6 -p-cymene){κ-(P)-PPh 3 - n (OCH 2 CH 2 NMe 3 ) n }][SbF 6 ] n [n = 1 (4a), 2 (4b) or 3 (4c)] have been prepared from the neutral precursors [RuCl 2 (η 6 -p-cymene){κ-(P)-PPh 3 - n (OCH 2 CH 2 NMe 2 ) n }] [n = 1 (2a), 2 (2b) or 3 (2c)] and Mel via quaternization of the nitrogen atom of the terminal aminoalkyl groups, and subsequent counteranion exchange by the treatment with AgSbF 6 . Complexes 2a-c and 4a-c have proven to be highly active catalysts for isomerization of allylic alcohols in THF and aqueous media, respectively. Moreover, the water-soluble catalysts 4a-c can be reused after a simple extraction process at the end of the reaction. In particular, 4c presents a remarkable capability to be recycled, being active during 10 successive runs.