Cesium carbonate → (S)-tert-Butyl 2-(6-(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-2-yl)-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-2-yl)pyrrolidine-1-carboxylate

Participants

Reaction Conditions

Reaction Steps

In a microwave vial, 2,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalene (57 mg, 0.150 mmol), a mixture of (S)-tert-butyl 2-(6-bromo-3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-2-yl)pyrrolidine-1-carboxylate and (S)-tert-butyl 2-(6-bromo-142-(trimethylsilyl)ethoxy)methyl)-1H-imidazo[4,5-b]pyridin-2-yl)pyrrolidine-1-carboxylate (112 mg), cesium carbonate (147 mg, 0.450 mmol) and dicyclohexyl(2′,6′-dimethoxybiphenyl-2-yl)phosphine (12.3 mg, 0.030 mmol) were dissolved into THF (3 mL) and water (0.3 mL). An additional 1.5 mL of THF was added and the reaction was sparged with bubbling nitrogen until ˜2 mL had evaporated away. To the clear solution was added palladium (II) acetate (3.37 mg, 0.015 mmol). The vial was flushed with nitrogen, sealed and then heated with microwave irradiation at 120° C. for 30 min. The reaction was diluted with EtOAc (˜3 mL) and washed with water (2 mL) and brine (2 mL). The reaction was dried (MgSO4), filtered and concentrated to a yellow oil which was purified by flash chromatography (12 g SiO2, 25-75% EtOAc/hexanes) to yield (2S,2′S)-tert-butyl 2,2′-(6,6′-(naphthalene-2,6-diyl)bis(3-((2-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridine-6,2-diyl))dipyrrolidine-1-carboxylate (74 mg) as a clear colorless oil (mixture of SEM regioisomers) and (S)-tert-butyl 2-(6-(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-2-yl)-342-(trimethylsilyl)ethoxy)methyl)-3H-imidazo[4,5-b]pyridin-2-yl)pyrrolidine-1-carboxylate (32 mg) as a colorless oil (mixture of SEM regioisomers). Each was used without further purification.

Provenance & Evidence