Triruthenium carbonyl clusters derived from chiral aminooxazolines: synthesis and catalytic activity

Abstract

Treatment of [Ru₃(CO)₁₂] with the chiral aminooxazolines (+)-2-amino-(4R)-phenyl-2-oxazoline (H₂amphox), (+)-2-amino-(4R,5S)-indanyl-2-oxazoline (H₂aminox) and (+)-2-(2′-anilinyl)-(4R,5S)-indanyl-2-oxazoline (H₂aninox) in THF at reflux temperature, affords the complexes [Ru₃(µ-H)(µ₃-κ²-Hox-N,N)(CO)₉] (H₂ox = H₂amphox, 1; H₂aminox, 2) and [Ru₃(µ-H)(µ-κ²-Haninox-N,N)(CO)₉] (3). In all cases, the activation of an N–H bond has occurred and the resulting amido fragment spans an edge of the metal triangle, while the N atom of the oxazoline ring is attached to the remaining metal atom (as in 1 and 2), or to one of the metal atoms of the bridged edge (as in 3). The use of 1–3 as catalyst precursors in the asymmetric hydrogen-transfer reduction of acetophenone and in the asymmetric cycloaddition of cyclopentadiene and acroleine is reported.