Trimethylphosphine → triethyl [1-[(3-iodophenyl)methyl]-2-(1-methylethyl)-4,5,6,7-tetrahydro-1H-benzimidazol-7-yl]methanetricarboxylate

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of Intermediate 91 (5.7 g) in Toluene (50 mL) and 2-Methyltetrahydrofuran (2-MeTHF) (50 mL) under nitrogen was added triethyl methanetricarboxylate (6.14 mL) followed by trimethylphosphine (2.54 mL). The reaction mixture was then cooled to −78° C. and DIAD (5.68 mL) was added dropwise over 12 min. The reaction mixture was allowed to continue stirring at −78° C. and under nitrogen for a further 40 min. The reaction mixture was then allowed to warm to room temperature and allowed to stir for a further 2 hours while still under nitrogen. The reaction mixture was then concentrated in vacuo before being partitioned between DCM (50 mL) and water (50 mL). The phases were separated and the aqueous layer was washed with further DCM (2×50 mL). The organic phases were combined, filtered through a hydrophobic frit and concentrated in vacuo to give 19.8 g of crude product as an orange oil. The sample was loaded in dichloromethane and purified on by column chromatography (silica) using a 0-100% ethyl acetate-cyclohexane gradient. The appropriate fractions were combined and evaporated in vacuo to give the required product 7.67 g as an off-white solid. LC/MS MH+ 611, Rt 3.54 min (5 min run).

Provenance & Evidence