4-Iodo-1-tritylimidazole → (2,3-dihydro-benzo[1,4]dioxin-5-yl)-(1-trityl-1H-imidazol-4-yl)-methanol

Participants

Reaction Steps

A mixture of 4-iodo-1-tritylimidazole (commercially available) (8.64 g, 19.8 mmol) in dichloromethane (100 mL) at −10° C. was treated with ethyl magnesium bromide (6.3 mL, 19 mmol, 3M in THF) and allowed to react for 45 m. A solution of 2,3-dihydro-benzo[1,4]dioxine-5-carbaldehyde (Intermediate A2) (2.6 g, 15.9 mmol) in dichloromethane was added via syringe at −10° C. and stirred for 45 m. The mixture was quenched with water (50 mL) and a sat. solution of ammonium chloride (50 mL). The residue was isolated in a typical aqueous workup and purified by chromatography on silica gel with 3 to 5% NH3-MeOH:CH2Cl2 to give (2,3-dihydro-benzo[1,4]dioxin-5-yl)-(1-trityl-1H-imidazol-4-yl)-methanol (Intermediate A3) as a solid, 2.9 g (40%).

Provenance & Evidence