Triisopropyl borate → tert-Butyl [5-(5,5-dimethyl-1,3,2-dioxaborinan-2-yl)pyridin-2-yl]methylcarbamate

Temperature

-78 °C

n-BuLi (27 mL, 2.5 M) was slowly added to a stirred solution of tert-butyl (5-bromopyridin-2-yl)methylcarbamate (17.7 g, 61.6 mmol) in THF (280 mL) at −78° C. under an argon atmosphere. After 5 min at −78° C., triisopropylborate (28.5 mL, 123 mmol) was added and the mixture was stirred at −78° C. for 1 h. Neopentyl glycol (6.4 g, 61.4 mmol) was added and the reaction mixture was allowed to reach rt and was stirred for 2.5 d. The reaction was quenched with water (300 mL). The phases were separated and the aqueous phase was extracted with DCM. The organic layer was concentrated and the residue was purified by two successive flash chromatographies (Heptane/EtOAc 9:1→1:4 and DCM/MeOH 24:1 respectively) to give the product (2.23 g) as a white solid. 1H NMR 8.57 (dd, 1 H) 7.94 (dd, 1 H) 7.65 (dd, 1 H) 3.76 (s, 4 H) 3.30 (s, 3 H) 1.47 (s, 9 H) 0.96 (s, 6 H).

1. customto reach rt
2. stirringwas stirred for 2.5 d
3. customThe reaction was quenched with water (300 mL)
4. customThe phases were separated
5. extractionthe aqueous phase was extracted with DCM
6. concentrationThe organic layer was concentrated
7. customthe residue was purified by two successive flash chromatographies (Heptane/EtOAc 9:1→1:4 and DCM/MeOH 24:1 respectively)

ORD record

ord-37334a508a4f4ac491e95aa5e3251566

Source dataset

uspto-grants-2015_02

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08957215B2