To a stirred solution of 3-amino-1-methyl-pyrrolidin-2-one (3258.49 mg, 28.55 mmol) in methanol (8 mL) was added 4-bromo-3-methyl-pyridine-2-carbaldehyde (which may be prepared as described in Description 7) (5710 mg, 28.55 mmol), phenyl vinyl sulfone (4801.68 mg, 28.55 mmol), and calcium triflate (482.74 mg, 1.43 mmol). The reaction was stirred for 5 minutes. Triethylamine (3.97 mL, 28.55 mmol) was then added [caution—slight exotherm observed], and the reaction was stirred for 15 minutes. A large amount of solid was observed to precipitate out of the reaction, this was sonicated and stirred for a further 15 minutes. The solid was then filtered off, and washed with additional methanol (approximately 10 mL). The pale cream solid was then washed with diethyl ether (10 mL), and air dried for 10 minutes to give a colourless solid, then dissolved in MeOH (8 mL), and treated with phenyl vinyl sulfone (4801.68 mg, 28.55 mmol), calcium triflate (482.74 mg, 1.43 mmol) and lastly triethylamine (3.97 mL, 28.55 mmol). The reaction mixture was then stirred at room temperature for 16 hours. The solid was filtered off, and washed with Et2O (10 mL). The solid was then air dried for 15 minutes on the sinter to afford 7-(benzene-sulfonyl)-8-(4-bromo-3-methyl-2-pyridyl)-3-methyl-3,9-diazaspiro[4.4]nonan-4-one (D8) (3520 mg, 7.58 mmol, 26.5% yield);
