Trimethyl borate → HCID 90412649, compound

Participants

Reaction Conditions

Reaction Steps

To a 100 mL round-bottom 3-neck flask equipped with nitrogen inlet/outlet, stir bar, and thermocouple with temperature controller was charged 3.0877 g of compound 8 (3 mmol, 1.0 eq) and 30 mL tetrahydrofuran (10 V). Reaction was cooled to 0° C. To this solution was added 6.98 mL (9 mmol, 2.4 eq) of isopropylmagnesium chloride lithium chloride complex, 1.3 M in THF slowly over 15 minutes. The reaction was stirred at 0° C. for 1 hour. An HPLC assay indicated the formation of intermediate. 1.05 mL of trimethylborate (9 mmol, 2.5 eq) was added to the reaction. An HPLC assay after 1 hour at 0° C. indicated that the reaction was completed. Quenched reaction with saturated aqueous ammonium chloride solution (3V). The ice bath was removed and the reaction was warmed to room temperature. The reaction was charged with DI water (3V) and ethyl acetate (6V). The layers were separated and the aqueous layer was back-extracted with ethyl acetate (6V). The organic phases were combined and washed with brine (3V) and dried over MgSO4. The resulting mixture was filtered. The filtrate was concentrated to dryness with a rotary evaporator. Obtained 2.87 grams (100% crude yield), 96 A % purity of [(3aR,6S,6aR)-6-[tert-butyl(diphenyl)silyl]oxy-2,2-dimethyl-4-(trityloxymethyl)-6,6a-dihydro-3aH-cyclopenta[d][1,3]dioxol-5-yl]boronic acid (compound 9c-1).

Provenance & Evidence