Following the general procedure, treatment of isoquinoline (0.064 g, 59 μL, 0.50 mmol) and 4-chlorobenzaldehyde (0.105 g, 0.75 mmol) with 4,5-dimethyl-2-(trimethylsilyl)phenyl trifluoromethanesulfonate (0.196 g, 0.60 mmol) in the presence of KF (0.070 g, 1.2 mmol) and 18-crown-6 (0.317 g, 1.2 mmol) in THF (2.0 mL) at −10° C. to room temperature for 12 hrs followed by flash column chromatography (Pet. ether/EtOAc=90/10) of the crude reaction mixture afforded 8,9-dimethyl-6-phenyl-4bH,6H-benzo[4,5][1,3]oxazino[2,3-a]isoquinoline as inseparable mixture of diastereomers as a yellow solid (0.127 g, 68% yield, dr determined by 1H NMR analysis of crude reaction mixture is 3:2).
