Imidazole → (7S,10R)-2-(tert-Butyldimethylsiloxy)-7,8,9,10-tetrahydro-9,9-dimethoxy-7-methyl-10-phenanthridinol

Participants

Reaction Conditions

Reaction Steps

Imidazole (1.01 g, 14.8 mmol, 2.60 equiv) and t-butyldimethylsilyl chloride (1.11 g, 7.39 mmol, 1.30 equiv) were added sequentially to a solution of (7S,10R)-7,8,9,10-tetrahydro-9,9-dimethoxy-7-methyl-2,10-phenanthridinediol (16, 1.64 g, 5.69 mmol, 1 equiv) in N,N-dimethylformamide (10 mL) at 23° C. After stirring for 1 h at 23° C., the reaction mixture was partitioned between water (100 mL) and ethyl acetate (100 mL). The aqueous layer was separated and extracted further with two 100-mL portions of ethyl acetate. The combined organic layers were dried over sodium sulfate and were concentrated. The residue was purified by flash column chromatography (30% ethyl acetate-hexanes) to afford (7S,10R)-2-(tert-butyldimethylsiloxy)-7,8,9,10-tetrahydro-9,9-dimethoxy-7-methyl-10-phenanthridinol (17) as a light yellow foam (2.10 g, 91%). ##STR27##

Provenance & Evidence