dimethyl 2-(1',1'-dimethylallyl)malonate → Dimethyl malonate

Participants

Reaction Steps

A mixture of bis(dibenzalacetone)palladium (0) (0.23 g, 0.4 mmole) and triphenylphosphine (0.84 g, 3.2 mmoles) in tetrahydrofuran (10 ml) is stirred at room temperature under argon for a few minutes to generate the catalytically active species. To the catalyst solution is added 2-methyl-3-buten-2-yl acetate (51.27 g, 400 moles) prepared according to Example 1 and a tetrahydrofuran solution of preformed dimethyl sodiomalonate prepared from sodium hydride (10.77 g) and dimethyl malonate (59.45 g, 450 mmoles). The resulting solution is maintained at reflux overnight under argon. The solvent (tetrahydrofuran) is removed by distillation and the residue after quenching with water is extracted with ether. After drying the ether is evaporated to leave 90 g of residue. Distillation at reduced pressure gives 69.0 g (86.1 percent) of colorless liquid (boiling point 110° C., 3.5 mm) shown by gas-liquid chromatography, infrared and nuclear magnetic resonance to be a 3:1 mixture of dimethyl(1,1-dimethylallyl)malonate and dimethyl(3,3-dimethylallyl)malonate.

Provenance & Evidence