Methyl Acrylate → (E)-3-{1'-tert-butoxycarbonyl-3,4-dihydro-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4'-piperidin]-6-yl}-acrylic acid methyl ester

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Reaction Steps

6-Bromo-3,4-dihydro-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-1′-carboxylic acid tert-butyl ester (5.00 g, 12.6 mmol) was dissolved in hot DMF (15 ml) and then TEA (5.26 ml, 37.8 mmol), tris(o-tolyl)phosphine (153 mg, 0.504 mmol), Pd(OAc)2 (56 mg, 0.25 mmol) and methyl acrylate (3.25 g, 37.8 mmol) were added at RT. The mixture was heated at 100° C. for 6 h under N2 with a further addition of tris(o-tolyl)phosphine (153 mg, 0.504 mmol) and Pd(OAc)2 (56 mg, 0.25 mmol) after three hours) and then partitioned between brine and AcOEt. The organic phase was rinsed with water and brine, dried over Na2SO4 and evaporated. The residue was triturated in AcOEt and petroleum ether to give (E)-3-{1′-tert-butoxycarbonyl-3,4-dihydro-4-oxo-spiro[2H-(1,3)-benzoxazine-2,4′-piperidin]-6-yl}-acrylic acid methyl ester (5.05 g)

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