In a two-necked 500 mL round-bottomed flask maintained under nitrogen, chloroform (10 mL), magnesium triflate (0.161 g, 0.5 mmol) and water (0.036 mL, 2.0 mmol) were added. To this stirred solution, (3aS,3a′S,8aR,8a′R)-2,2′(cyclopropane-1,1-diyl)bis(8,8a-dihydro-3aH-indeno[1,2-d]oxazole) (bis(oxazoline)) (0.196 g, 0.55 mmol) was added and the reaction mixture stirred for 1 hour. At the end of 1 hour, chloroform (30 mL) and molecular sieves (2 g) were added and the mixture stirred for another 90 mins. (E)-Methyl-2-nitro-3-(2,4,6-trimethoxyphenyl)acrylate (3.1 g, 0.01 mol), dimethyl malonate (1.92 g, 0.014 mol) and N-methylmorpholine (0.06 g, 0.6 mmol) were added and the reaction mixture was stirred for 12 hours followed by heating at 40° C. for 4 hours. Petroleum ether (15 mL) was added to the reaction mixture, stirred for 10 mins. and the mixture filtered. The molecular sieves were washed with methyl-t-butyl ether and the combined organic layer was washed with 5% phosphoric acid (10 mL) and brine (15 mL). The organic layer was concentrated under reduced pressure to give an oil. The oil was dissolved in methanol (10 mL), cooled and filtered to give a white crystalline solid.
