Triisopropyl borate → (5-{[(Tert-butoxy-carbonyl)amino]methyl}-2-chloropyridin-4yl)boronic acid

Participants

Reaction Conditions

Reaction Steps

Tert-butyl[(6-chloropyridin-3-yl)methyl]carbamate (1.00 g, 0.004 mol) was dissolved in anhydrous tetrahydrofuran (20 mL) in an oven-dried 50-mL round-bottomed flask. The solution was stirred under an atmosphere of nitrogen and cooled to at −78° C. Tert-butyllithium (1.7 M in pentane, 5.1 mL, 0.009 mol) was slowly added via syringe. The reaction solution turned yellow, then dark orange during the addition. The resulting solution was stirred at −77° C. for 10 min, then was slowly warmed to −20° C. Triisopropyl borate (3.79 mL, 0.017 mol) was added quickly via syringe and the mixture was allowed to warm to room temperature with stirring. The reaction was cooled to 0° C. and quenched by the slow addition of 1.00 M of hydrochloric acid in water (8.65 mL) with good stirring. The reaction mixture was then added to water (100 mL) in a separatory funnel and was extracted with ethyl acetate (3×75 mL). The extracts were combined, dried over sodium sulfate, filtered, concentrated and dried under vacuum to leave 1.15 g (97% yield) (5-{[(tert-butoxy-carbonyl)amino]methyl}-2-chloropyridin-4yl)boronic acid as an orange foam. The product structure was confirmed by NMR and MS and used without further purification.

Provenance & Evidence