[[(4R,5R)-2,2-Dimethyl-1,3-dioxolane-4,5-diyl]bis(methylene)]bis(diphenylphosphine)

Typical procedure (entry 1): Under a flow of argon, a 10 ml dried screw-cap flask is charged with [Rh(COD)Cl]₂ (9.8 mg), (-)-DIOP (19.7 mg), Cs₂CO₃ (12.9 mg) and 4-methoxybenzoic acid (67 mg). Freshly distilled 1,2-dichloroethane (4.4 mL) is added and the mixture is cooled to -3 °C, followed by the addition of cyclohexyl allene (77 micro-L). The flask is then sealed and the mixture is stirred for 48 h at -3 °C. The reaction mixture is directly flushed through a plug of silica gel and washed with dichloromethane. The light yellow solution is concentrated under vacuum, the crude mixture is purified by flash chromatography on silica gel (eluent: cyclohexane/EtOAc = 25/1) to give (R)-1-cyclohexylallyl 4-methoxybenzoate (100 mg, 83 % yield, 96 % ee)