Dichloro(p-cymene)ruthenium(II) Dimer

Typical Procedure:
Acetophenone (0.4 mmol), p-toluenesulfonyl azide (0.2 mmol), [RuCl₂(p-cymene)]₂ (4.9 mg, 4 mol%), AgNTf₂ (12.5 mg, 16 mol%), NaOAc (3.3 mg, 20 mol%), and 1,2-dichloroethane (0.5 mL) are added to a screw-capped vial equipped with a spinvane triangular-shaped Teflon stirbar. The reaction mixture is stirred in a preheated oil bath at 80 °C for 12 h and then cooled to room temperature, filtered through a pad of Celite, and washed with ethyl acetate (10 mL×3). The filtrate is concentrated under reduced pressure and the residue is purified by chromatography on silica gel (n-hexane : EtOAc = 3 : 1) to give the desired product (56.1 mg, Y. 97%).

Typical Procedure:
A mixture of N-methoxybenzamide (0.50 mmol, 1.0 eq.), the alkyne (if solid) (0.60 mmol, 1.2 eq.), [RuCl₂(p-cymene)]₂ (9.2 mg, 0.015 mmol, 3.0 mol%) and NaOAc (8.2 mg, 0.10 mmol, 20.0 mol%) are placed in a Schlenk tube equipped with a stir bar. Dry MeOH (2.5 mL) is added (followed by the alkyne if it is a liquid) and the mixture is stirred at room temperature for 8 h under an argon atmosphere. Afterwards, the mixture is diluted with CH₂Cl₂ and transferred to a round-bottomed flask. Silica is added to the flask and volatiles are evaporated under reduced pressure. The purification is performed by flash column chromatography on silica gel (EtOAc : petroleum ether=1:5 to 1:1, typically) to give the corresponding pure products.