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

Temperatur

-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 δ 8.57 (dd, 1H) 7.94 (dd, 1H) 7.65 (dd, 1H) 3.76 (s, 4H) 3.30 (s, 3H) 1.47 (s, 9H) 0.96 (s, 6H).

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-Eintrag

ord-d26c8a4f37e7411e99d8d605af81f8c3

Quelldatensatz

uspto-grants-2012_04

DOI

10.6084/m9.figshare.5104873.v1

Patentnummer

US08163928B2