diethyl 2-[(2,2-dichloro-3-oxocyclobutyl)methyl]propanedioate

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

Procedure: To a stirred suspension of Cu.Zn (1.771 g, 13.73 mmol) and diethyl 2-allylmalonate (1.084 mL, 5.49 mmol) in anhydrous Et2O (20 mL) at reflux was added a solution of phosphorus oxychloride (1.127 mL, 12.09 mmol) and 2,2,2-trichloroacetyl chloride (1.357 mL, 12.09 mmol) in Et2O (10 mL) dropwise through an addition funnel over 2 h. The resulting mixture was then heated at reflux overnight. After cooling to room temperature, the mixture was filtered through CELITE® and washed with EtOAc. The filtrate was concentrated and the residue was purified by silica gel column chromatography (80 g, EtOAc/hexane=0-50%) to afford Preparation 7A (1.59 g, 93%). at reflux The resulting mixture was then heated at reflux overnight the mixture was filtered through CELITE® washed with EtOAc The filtrate was concentrated the residue was purified by silica gel column chromatography (80 g, EtOAc/hexane=0-50%) to afford

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

Procedure: To a stirred suspension of Cu.Zn (1.771 g, 13.73 mmol) and diethyl 2-allylmalonate (1.084 mL, 5.49 mmol) in anhydrous Et2O (20 mL) at reflux was added a solution of phosphorus oxychloride (1.127 mL, 12.09 mmol) and 2,2,2-trichloroacetyl chloride (1.357 mL, 12.09 mmol) in Et2O (10 mL) dropwise through an addition funnel over 2 h. The resulting mixture was then heated at reflux overnight. After cooling to room temperature, the mixture was filtered through CELITE® and washed with EtOAc. The filtrate was concentrated and the residue was purified by silica gel column chromatography (80 g, EtOAc/hexane=0-50%) to afford Preparation 7A (1.59 g, 93%). at reflux The resulting mixture was then heated at reflux overnight the mixture was filtered through CELITE® washed with EtOAc The filtrate was concentrated the residue was purified by silica gel column chromatography (80 g, EtOAc/hexane=0-50%) to afford

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

Procedure: To a stirred suspension of Cu.Zn (1.771 g, 13.73 mmol) and diethyl 2-allylmalonate (1.084 mL, 5.49 mmol) in anhydrous Et2O (20 mL) at reflux was added a solution of phosphorus oxychloride (1.127 mL, 12.09 mmol) and 2,2,2-trichloroacetyl chloride (1.357 mL, 12.09 mmol) in Et2O (10 mL) dropwise through an addition funnel over 2 h. The resulting mixture was then heated at reflux overnight. After cooling to room temperature, the mixture was filtered through CELITE® and washed with EtOAc. The filtrate was concentrated and the residue was purified by silica gel column chromatography (80 g, EtOAc/hexane=0-50%) to afford Intermediate S-1A (1.59 g, 93%). 1H NMR (400 MHz, chloroform-d) δ 4.32-4.23 (m, 4H), 3.58 (dd, J=8.9, 6.1 Hz, 1H), 3.47-3.32 (m, 1H), 3.16-2.92 (m, 2H), 2.51 (ddd, J=14.3, 7.2, 6.1 Hz, 1H), 2.40-2.25 (m, 1H), 1.36-1.30 (m, 6H). at reflux The resulting mixture was then heated at reflux overnight the mixture was filtered through CELITE® washed with EtOAc The filtrate was concentrated the residue was purified by silica gel column chromatography (80 g, EtOAc/hexane=0-50%) to afford Intermediate S-1A (1.59 g, 93%)