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 [RuCl2(η6‐p‐cymene){κ‐(P)‐PPh3n(OCH2CH2NMe3)n}][SbF6]n [n=1 (4a), 2 (4b) or 3 (4c)] have been prepared from the neutral precursors [RuCl2(η6‐p‐cymene){κ‐(P)‐PPh3‐n(OCH2CH2NMe2)n}] [n=1 (2a), 2 (2b) or 3 (2c)] and MeI via quaternization of the nitrogen atom of the terminal aminoalkyl groups, and subsequent counteranion exchange by the treatment with AgSbF6. 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.