1,8-Diazabicyclo(5.4.0)undec-7-ene → (7R,7aR)-4-[7-(tert-Butyldimethylsilanyloxy)-7a-methyl-1,3-dioxotetrahydropyrrolo[1,2-c]imidazol-2-yl]-2-chloro-3-methylbenzonitrile

Participants

Reaction Steps

A solution of (2R,3R)-3-(tert-Butyldimethylsilanyloxy)-2-methyl-pyrrolidine-1,2-dicarboxylic acid 1-tert-butyl ester-2-methyl ester (60A) (52 mg, 0.14 mmol) in CH2Cl2 (1.5 mL) and TFA (0.5 mL) was stirred at rt for 2 h. The reaction was concentrated under reduced pressure and dried under vacuum. The residue was dissolved in CH2Cl2 (1.5 mL) and Hunig's base (60 μL, 0.35 mmol) was added. After stirring at rt for 10 min, 2-chloro-4-isocyanato-3-methylbenzonitrile (34 mg, 0.18 mmol) was added and the reaction was stirred at rt overnight. The reaction was treated with DBU (40 μL, 0.27 mmol) and was stirred for 4 h at rt then concentrated under reduced pressure. The residue was purified via chromatography (silica gel) eluting with 30% EtOAc in hexane to provide the title compound (54 mg). LC/MS m/z 434 [M+H]+.

Provenance & Evidence