Triacetoxyperiodinane → Ammonium Hydroxide

Participants

Reaction Steps

To a solution of 4-{hydroxy-[5-triisopropylsilanyl-2-(3,4,5-trimethoxy-phenyl)-5H-pyrrolo[2,3-b]pyrazin-7-yl]-methyl}-4-methyl-piperidine-1-carboxylic acid tert-butyl ester from above (950 mg, ˜1.4 mmol) in CH2Cl2 (5 mL) was added Dess-Martin periodinane (900 mg, 2.1 mmol) portionwise. The resultant orange suspension was allowed to stir for 1 h and partitioned between 1:1 saturated Na2S2O3:saturated NaHCO3 and CH2Cl2. The aqueous phase was extracted with CH2Cl2 and the combined organic phases were dried over Na2SO4 and concentrated to give a tan solid. The crude product was purified by flash chromatography using 25 g of silica gel and 0-30% of 9.5:0.5 MeOH:conc NH4OH in CH2Cl2 as eluant to afford 150 mg of impure 4-methyl-4-[2-(3,4,5-trimethoxy-phenyl)-5H-pyrrolo[2,3-b]pyrazine-7-carbonyl]-piperidine-1-carboxylic acid tert-butyl ester, M+Na 533, and 0.24 g of impure 4-methyl-4-[5-triisopropylsilanyl-2-(3,4,5-trimethoxy-phenyl)-5H-pyrrolo[2,3-b]pyrazine-7-carbonyl]-piperidine-1-carboxylic acid tert-butyl ester, M+Na 689.

Provenance & Evidence