Bis(tricyclohexylphosphine)bezylidene ruthenium (IV) dichloride (Grubbs type I catalyst, from Lancaster)
dichloromethane (distilled from CaH₂)
diethyldiallylmalonate (Aldrich)

To Grubbs catalyst (10mg, ~5 mol%)in a 5 mL round bottomed flask equipped with a reflux condenser under nitrogen stirring in dichloromethane (2ml) is added diethyldiallylmalonate (0.23mmol, 0.054ml) and the purple solution refluxed until completion (TLC, about 1 hour), then cooled to room temperature and concentrated in vacuum. Purification is by column chromatography eluting with 10%EtOAc/PE to give yields of 90% (44 mg) or more.

The ring closing metathesis reaction has seen massive use in organic chemistry in the last few years. This is one of the original reactions using the Grubbs type I catalyst which is commercially available and quite stable in air, although it should be stored under an inert atmosphere. This reaction is very easy, although a little extra care is required when carrying out TLC analysis as the product and reactant run very closely. More hindered substrates require further time, but the reaction can be carried out at reduced temperatures for heat sensitive substrates. More recently, N-heterocyclic carbene ruthenium catalysts have been developed, which are considerably more active than the the original catalysts, although not as easy to handle.

¹HNMR(300MHz, CDCl₃) 5.8 (2H,d) 4.35 (4H, q) 3.2 (4H, d) 1.4 (6H, t).

Scholl M, Trnka TM, Morgan JP, Grubbs RH Tetrahedron Lett. 1999, 40, p2247-2250

Original reference: R.H.Grubbs, S.T.Nguyen, J.W.Ziller J.Am.Chem.Soc. 1993 p9858 Reviews: R.H.Grubbs, S.Chang Tetrahedron 1998 p.4413 S.K.Armstrong J.Chem.Soc. Perkin Trans 1 1998 p.371 Carbene type catalysts: R.H.Grubbs, M.Scholl, T.M.Trnka, J.P.Morgan Tetrahedron Lett. 1999 p.2247 Preparation of carbene type catalysts: R.H.Grubbs, J.P.Morgan Organic Letters 2000 p.3153