Reaction Steps
A 1 L round-bottom flask equipped with an air cooled reflux condenser outfitted with a nitrogen inlet adapter was charged with palladium(II) acetate (0.441 g, 1.97 mmol), Xantphos (1.71 g, 2.95 mmol), Cs2CO3 (22.4 g, 68.8 mmol), evacuated and filled with nitrogen (three cycles), and then 1,4-dioxane (131 mL) was added followed by an additional three cycles of evacuation and nitrogen backfilling. The suspension was stirred at rt for about 15 min and then TEA (0.41 mL, 3.0 mmol) was added. After an additional 15 min of stirring at rt, a solution of benzophenone imine (9.90 mL, 59.0 mmol) and rac-(7aS,11aS)-3-bromo-11a-vinyl-7,7a,8,10,11,11a-hexahydro-6H-spiro[dibenzo[b,d]oxepine-9,2′-[1,3]dioxolane] (18.0 g, 49.1 mmol) (prepared as described in WO 2012125797) in dioxane (65 mL) was added and the reaction mixture was heated to about 100° C. for about 18 h. The reaction mixture was diluted with EtOAc (300 mL) and filtered. The filtered solid was washed with EtOAc (2×50 mL) and the combined filtrate was concentrated under reduced pressure. The crude material was purified on silica gel (330 g, eluted with 0 to 30% EtOAc in heptane). Collection and concentration of the appropriate fractions gave rac-(7aR,11aR)—N-(diphenylmethylene)-11a-vinyl-7,7a,8,10,11,11a-hexahydro-6H-spiro[dibenzo[b,d]oxepine-9,2′-[1,3]dioxolan]-3-amine (85, R2=Vinyl) (17.8 g, 78%). LC/MS, method 3, 2.98 min, MS m/z 466 (M+H)+. 1H NMR (400 MHz, CDCL3) δ 7.86-7.79 (m, 2H), 7.58-7.50 (m, 1H), 7.49-7.40 (m, 2H), 7.38-7.26 (m, 3H), 7.19-7.13 (m, 2H), 7.10-7.04 (m, 1H), 6.73-6.58 (m, 1H), 6.49-6.44 (m, 1H), 5.97-5.85 (m, 1H), 4.96-4.88 (m, 1H), 4.42-4.32 (m, 1H), 4.08-3.98 (m, 1H), 3.99-3.86 (m, 4H), 3.71-3.59 (m, 1H), 2.41-2.30 (m, 1H), 2.29-2.19 (m, 1H), 2.16-2.08 (m, 1H), 1.88-1.60 (m, 4H), 1.61-1.46 (m, 1H), 1.44-1.35 (m, 1H).
