A mixture of 1-chloro-5-methyl-3-phenylhex-5-en-3-ol (2.9 g, 13 mmol), (S)-1-bromo-4-(1-isocyanatoethyl)benzene (3.5 g, 16 mmol), and DBU (8 g, 33 mmol) in THF (80 mL) was heated at reflux overnight. The mixture was diluted with EtOAc, and washed with 1 N aq HCl. The aqueous phase was extracted with EtOAc (3×), and the combined organic phase was dried over Na2SO4. After the solvents were evaporated, the crude product was purified by column chromatography to give (R)-3-((S)-1-(4-bromophenyl)-ethyl)-6-(2-methylallyl)-6-phenyl-1,3-oxazinan-2-one (1.62 g, yield: 30%).
