Acetyl chloride → 1,1-Dimethylethyl 2-acetyl-2,3-dihydrospiro[isoquinoline-4(1H),4′-piperidine]-1′-carboxylate

Participants

Reaction Steps

tert-Butyl 2,3-dihydro-1H-spiro[isoquinoline-4,4′-piperidine]-1′-carboxylate 6a (2.128 g, 6.28 mmol) was dissolved in anhydrous dichloromethane (30 mL), cooled in an ice-H2O bath and treated dropwise with a solution of acetyl chloride (518 mg, 6.59 mmol) in anhydrous dichloromethane (5 mL). The reaction was then treated dropwise with a solution of triethylamine (1.335 g, 13.2 mmol) in anhydrous dichloromethane (5 mL). The reaction was stirred in the ice-H2O bath for 15 minutes, then diluted with dichloromethane (100 mL), washed with H2O, saturated NaHCO3 (3×), saturated brine, dried (Na2SO4) and filtered. The filtrate was concentrated under reduced pressure to afford crude tert-butyl 2-acetyl-2,3-dihydro-1H-spiro[isoquinoline-4,4′-piperidine]-1′-carboxylate 6b as a colorless oil (2.732 g, quantitative yield). LC/MS m/z [M+H]+ 345.2 retention time 2.98 min (10-99% CH3CN—H2O gradient, with 0.05% TFA, 5 min).

Provenance & Evidence