| 19199302 |
Wu CY, Chou HH, Lin YC, Wang Y, Liu YH: Reactions of ruthenium vinylidene and acetylide complexes containing trichloromethyl groups: preparation of a cyclobutenonyl complex by solid-state photolysis. Chemistry. 2009;15(13):3221-9.
Solid-state route to a cyclobutenone: Ruthenium perchlorocyclobutenonyl complex 2 is obtained by solid-state photoisomerization of ruthenium trichloroacetyl acetylide complex 1. The four-membered ring is sufficiently robust that transfer of the intact ligand could be readily achieved in a reaction of 2 with an enyne. Cyclobutenedionyl complex 3 was obtained by hydrolysis of 2 in H (2) O/THF.New reactions were observed for the cationic gamma-hydroxyvinylidene complex [Ru (2)]==C==CHC (OH)(CCl (3))(2) (+) (2, [Ru (2)]=CpRu (PPh (3))(2)). A rare chloroform elimination was observed when 2 was treated with nBu (4) NOH to give neutral acetylide complex [Ru (2)]--C [triple chemical bond] CC (==O) CCl (3) (3). Solid-state photoinduced isomerization of 3 generated ruthenium perchlorocyclobutenonyl complex [Ru (2)]--C (4) Cl (3) O (4) in high yield. This transformation was analyzed by DFT calculations, and 4 was found to be 4.22 kcal mol (-1) more stable in terms of Gibbs free energy than 3. In the coupling reaction of 4 with 2-methyl-1-buten-3-yne the four-membered cyclic ligand is transferred to the enyne to give substituted eta (3)-butadienyl complex 5 containing a cyclobutenonyl group. This coupling product could be removed from the metal by HCl. Deprotonation of 2 gave gamma-hydroxyacetylide complex [Ru (2)]--C [triple chemical bond] CC (OH)(CCl (3))(2) (9). In the photolysis of 9 phosphine dissociation is followed by addition of HCl to give neutral vinylidene complex Cl [Ru (1)]==C==CHC (OH)(CCl (3))(2) (10, [Ru (1)]=Cp (PPh (3)) Ru). Complex 4 catalyzed the coupling reaction of dimethyl acetylenedicarboxylate with styrene yielding the diene PhCH==CHC (CO (2) Me)==CHCO (2) Me. Solid-state structures of 3-6 and 10 were determined by single-crystal X-ray diffraction analysis. |
81(1,1,1,1) |