2,2'-(Naphthalene-2,6-diyl)bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolane) → HCID 178451934, compound

Participants

Reaction Steps

A solution of (S)-tert-butyl 2-(5-(4-bromophenyl)-4-chloro-1H-imidazol-2-yl)pyrrolidine-1-carboxylate (1.04 g, 2.44 mmol) and 2,6-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalene (0.926 g, 2.44 mmol) in DME (10 mL) and water (2 mL) was degassed under vacuum for 10 min. The mixture was heated at ca ˜80° C., Pd(Ph3P)4 (0.282 g, 0.244 mmol) was added under a stream of nitrogen and the reactor was sealed. The heating was pursued further to 130° C. for 8 h. Additional Pd(PPh3)4 (100 mg) was added and the heating was pursued overnight. The DME was removed in vacuo and the crude material was partitioned between EtOAc/H2O. The layers were separated and the aqueous layer was extracted several times with EtOAc. The combined organic extracts were dried over Na2SO4 and evaporated in vacuo. The residue was purified by flash column chromatography (BIOTAGE®), eluting with a gradient of 0 to 100% EtOAc/hexanes to afford the partially pure (S)-tert-butyl 2-(4-chloro-5-(4-(6-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)naphthalen-2-yl)phenyl)-1H-imidazol-2-yl)pyrrolidine-1-carboxylate contaminated with triphenylphosphine (292 mg). A small aliquot was purified further by a reverse phase HPLC (water/acetonitrile/TFA) to afford the pure title material. The remaining material was used in subsequent step without further purification. LC-MS retention time 2.227 min; m/z 598.46 (MH−) LC data was recorded on a Shimadzu LC-10AS liquid chromatograph equipped with a PHENOMENEX® Luna 10u C18 3.0×50 mm column using a SPD-10AV UV-Vis detector at a detector wave length of 220 nM. The elution conditions employed a flow rate of 4 mL/min, a gradient of 100% Solvent A/0% Solvent B to 0% Solvent A/100% Solvent B, a gradient time of 2 min, a hold time of 1 min, and an analysis time of 3 min where Solvent A was 10% MeOH/90% H2O/10 mM ammonium acetate and Solvent B was 10% H2O/90% MeOH/10 mM ammonium acetate. MS data was determined using a MICROMASS® Platform for LC in electrospray mode. 1H NMR (500 MHz, MeOD, TFA salt, partial NMR) δ ppm 3.71 (br s, 2H), 3.55 (br s, 2H), 2.45 (br s, 1H), 2.07-2.17 (m, 2H), 1.97-2.06 (m, 1H), 1.50 (s, 3H), 1.43 (m, 6H), 1.31 (br s, 6H).

Provenance & Evidence