(Dimethyl sulfide)trihydroboron → tert-Butyl 2,2-difluoro-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate

Participants

Reaction Conditions

Reaction Steps

Borane methyl sulfide complex (2M in THF, 2.69 mL) was added dropwise to a solution of tert-butyl 2,2-difluoro-3-oxo-1-oxa-4,9-diazaspiro[5.5]undecane-9-carboxylate (example 37, step b) (0.55 g) in THF (15 mL). The reaction mixture was heated at 55° C. under nitrogen for 25 minutes and then cooled to room temperature. The mixture was quenched by careful dropwise addition of methanol (5 mL). N1,N2-dimethylethane-1,2-diamine (0.633 g) was then added and the mixture heated at 70° C. for 40 minutes. The solvents were removed under reduced pressure and the residue was purified by flash silica chromatography using 4% methanol in dichloromethane with 1% triethylamine as solvent. Pure fractions were evaporated to dryness to afford the subtitled compound. Yield 0.32 g. Used directly.

Provenance & Evidence