To a flame-dried 250-mL Teflon-sealed Schlenk flask equipped with a magnetic stir bar was added crude methy enol ether SI-7 as a solution in EtOAc (64 mL, 0.2 M). To the reaction mixture was added Mn(OAc)3•2H2O (681 mg, 2.54 mmol, 0.2 equiv) and anhydrous TBHP (12.7 mL, 63.5 mmol, 5.0 equiv, 5.5 M in decane) at room temperature. The reaction vessel was then sealed, placed in a room temperature sonication bath for 5 minutes. Following this, the reaction flask was transferred to a 65 °C preheated oil bath.