Potassium Carbonate → HCID 125501437, compound

Participants

Reaction Steps

To a solution of 2,2,3,3,13,13,14,14-octamethyl-4,12-dioxa-8-thia-3,13-disilapentadecane 8-oxide in anhydrous dichloromethane (150 mL) was added trifluoroacetamide (7.60 g, 2 eq), magnesium oxide (5.256 g. 4 eq), rhodium acetate dimer (432 mg, 0.03 eq), and (diacetoxyiodo)benzene (15.75 g, 1.5 eq) under nitrogen atmosphere at room temperature. The greenish reaction mixture was stirred at room temperature for 18 hours. Then additional amount of trifluoroacetamide (3.0 g), rhodium acetate dimer (300 mg), (diacetoxyiodo)benzene (5.0 g), and anhydrous DCM (100 mL) was added. The mixture was stirred at room temperature for another 3 hours and then filtered through a pad of celite and silica gel. The pad was washed first with DCM followed by MeOH-DCM (1:5). The filtrate was concentrated and the brown oil was taken up into methanol (200 mL). Potassium carbonate (22.53 g, 5 eq) was added to the newly formed solution. After the mixture was stirred at room temp for 2 hours, it was filtered through a pad of celite and silica gel. The pad was washed first with DCM-EtOAC (1:1) followed by a later 10% (v/v) addition of MeOH with stirring of the sediment on top of the pad. The filtrate was concentrated and the residue mixture was treated with DCM-EtOAc (2:3) with stirring at room temp for 30 minutes. The mixture was filtered again through a pad of celite and silica gel. This filtration and concentration circle may be repeated a couple of times such that most of the solid by-product was removed and a reddish oil was obtained. Purification by a gradient column chromatography (EtOAc-HEX 1:20 to 1:1) provided the title compound as a redish oil (9.538 g) with a total yield of 72% for 4 steps.

Provenance & Evidence