dimethyl 2-ethylidenepropanedioate

Conditions: temp:110.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of [(R)-1-(N-Benzyl-carbamimidoyl)-2-methyl-propyl]-carbamic acid t-butyl ester (7.08 g, 23 mMol) in MeOH (15 mL) was added Dimethyl ethylidenemalonate (3.64 g, 23 mMol). The reaction was slowly heated to 110° C. allowing the MeOH to distill off. The reaction was stirred for 5 h at 110° C. then allowed to cool to RT. Purification by flash chromatography (25% EtOAc, hexane) gave the title compound (6.37 g, 64%) as an oil: ˜(3:1) mixture of diastereomers by LCMS; MS (ES) m/e 432.2 and 432.4 (M+H)+. to distill off to cool to RT Purification by flash chromatography (25% EtOAc, hexane)

Conditions: temp:110.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: To a solution of [(R)-1-(N-Benzyl-carbamimidoyl)-2-methyl-propyl]-carbamic acid t-butyl ester (7.08 g, 23 mMol) in MeOH (15 mL) was added Dimethyl ethylidenemalonate (3.64 g, 23 mMol). The reaction was slowly heated to 110° C. allowing the MeOH to distill off. The reaction was stirred for 5 h at 110° C. then allowed to cool to RT. Purification by flash chromatography (25% EtOAc, hexane) gave the title compound (6.37 g, 64%) as an oil: ˜(3:1) mixture of diastereomers by LCMS; MS (ES) m/e 432.2 and 432.4 (M+H)+. to distill off to cool to RT Purification by flash chromatography (25% EtOAc, hexane)