Fig. 6.

Mechanistic divergence between methoxy methylation and azido methylation. a: 21 (0.2 mmol), Cu(BF₄)₂•6H₂O (0.2 equiv), L1 (0.3 equiv), DCP (4.0 equiv), Na₂HPO₄ (0.2 equiv), MeOH (2.0 mL, c 0.1 M), 120 °C, 4 h; b: 21 (0.2 mmol), DTBP (0.8 mmol), LiN₃ (0.5 mmol), CuSO₄ (0.002 mmol, 0.1 equiv), L2 (0.06 mmol), tBuOH (2.0 mL, c 0.1 M), 120 °C