Barton-McCombie Reaction

STEP 1: A two-necked round-bottomed flask equipped with a magnetic stirring bar, a rubber septum, and an inlet adapter with a three-way stopcock was charged with the alcohol (1.28 mmol, 1.0 eq) and dry THF (16 mL). After addition of NaH (1.5 eq) to the solution at 0 ºC,  the resultant mixture was stirred at 0 ºC for 30 min, and CS2 (5.0 eq) was added at 0 ºC. After stirring for additional 1 h at room temperature, MeI (5.0 eq) was added and stirring was continued at room temperature for 24 h. Then, the reaction mixture was concentrated under reduced pressure to give a crude material, which was purified by silica gel column chromatography to afford the xanthate ester (91% yield).

STEP 2: A round-bottomed flask equipped with a magnetic stirring bar and an inlet adapter with a three-way stopcock was charged with the substrate (1.15 mmol, 1.0 eq) and dry toluene (80 mL). To the solution, AIBN (0.2 eq)  and n-Bu3SnH (2.0 eq) were added at room temperature. The reaction mixture was stirred at 90 ºC for 4 h, until complete consumption of starting material. The reaction was quenched with saturated aq NH4Cl. The reaction mixture was extracted with ethyl acetate three times. The combined organic extracts were washed with brine, dried over anhydrous sodium sulfate, and filtered. The filtrate was concentrated under reduced pressure to give the crude material, which was purified by silica gel column chromatography to afford the desired product (93% yield).