反应详情

To a solution of 3-[(E)-3-chloro-1-methyl-1-propenyl]benzonitrile (Preparation 34, 13.1 g, 69.6 mmol) in dichloromethane (20 ml) was added rhodium (II) acetate dimer (0.46 g, 1.0 mmol). To the mixture was added dropwise at room temperature over 8 h (via a syringe pump) a solution of ethyl diazoacetate (14.6 ml, 0.14 mol) in dichloromethane (20 ml). The solvent was removed in vacuo and the crude residue was then partially purified by silica column chromatography eluting with dichloromethane:hexane (80:20). This material was then dissolved in dichloromethane (20 ml) containing rhodium (II) acetate dimer (0.46 g, 1.0 mmol). To this mixture was added dropwise a solution of ethyl diazoacetate (14.6 ml, 0.14 mol) in dichloromethane (20 ml) at room temperature over 8 h. The mixture was concentrated in vacuo and the residue purified by silica column chromatography eluting with hexane:dichloromethane (80:20) and then hexane:diethyl ether (80:20) to give the title compound as a colourless oil which solidified on standing (5.82 g, 30%).

1. customThe solvent was removed in vacuo
2. customthe crude residue was then partially purified by silica column chromatography
3. washeluting with dichloromethane:hexane (80:20)
4. dissolutionThis material was then dissolved in dichloromethane (20 ml)
5. concentrationThe mixture was concentrated in vacuo
6. customthe residue purified by silica column chromatography
7. washeluting with hexane:dichloromethane (80:20)