To a DCM ( 20 mL ) solution of 4 ( 1.0 g , 0.87 mmol ) was added Me3SiOTf ( 0.35 mL , 1.94 mmol ) at rt and stirred for 2 h. The solvent was evaporated and the crude product was suspended in toluene , filtered , and dried under vacuum to afford 7 ( 1.13 g , 90 % ) . NMR spectroscopic data of this product were identical to that prepared by using 6 and ( Me3S)AuCl ( see above ) .