Triethylamine → tert-butyl 4-[(E)-4-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)but-3-enyl]-4,9-diazaspiro[5.5]undecane-9-carboxylate

Participants

Reaction Conditions

Reaction Steps

Tert-butyl 8-but-3-ynyl-3,8-diazaspiro[5.5]undecane-3-carboxylate (129.00 g, 420.95 mmoles), triethylamine (5.87 mL, 42.10 mmoles), and zirconocene chloride (10.86 g, 42.10 mmoles) are combined. To this is added 4,4,5,5-tetramethyl-1,3,2-dioxaborolane (64.13 mL 442.00 mmoles) via syringe. The reaction is then heated to 65° C. and stirred at this temperature for 24 hours. The heat is turned off and the reaction allowed to stir at ambient temperature for a further 24 hours. Dichloromethane (500 mL) is added and the resulting solution is filtered through a 10 cm pad of silica eluting with 20% ethyl acetate in dichloromethane (3×500 mL). The filtrate is concentrated under reduced pressure to provide the title compound (163.5 g; Yield 89%). Mass spectrum (m/z): 435.35 (M+1).

Provenance & Evidence