Tris(1,1-dimethylethyl)phosphine → HCID 68508241, compound

Participants

Reaction Steps

Under an inert atmosphere a 250 mL three necked round bottom flask (flame dried) with a magnetic stirring bar was charged with 4 g (22.7 mmol) 2-bromo-5-fluoropyridine, 11.7 g (45 mmol) ethyl 1-tert.-butyloxycarbonylpiperidine-4-carboxylate, 416 mg (0.04 mmol) tris(dibenzylideneacetone)palladium(0), 0.91 mL tri-tert-butylphosphine (1M in toluene) and 60 ml toluene. To the dark red solution, 50 mL lithium-bis-(trimethylsilyl)-amid (1M in hexane) was added dropwise during 1 h at 18 to 23° C. The dark brown reaction solution was stirred for 87 h at room temperature. The reaction was quenched with saturated aqueous NH4Cl-solution. The aqueous layer was separated and extracted once with 200 mL ethyl acetate. The organic layers were washed once with 150 mL brine, dried over Na2SO4, filtered off and concentrated under vacuum. The residue was purified on silica eluting with a gradient formed from heptane and TBME to yield after evaporation of the product fractions 4 g (50%) of the title compound as yellow viscous oil. MS ISP (m/e): 253.3 (M-Boc)/353.2 [(M+H)+].

Provenance & Evidence