Diisopropylamine → HCID 117603899, compound

Participants

Reaction Conditions

Reaction Steps

A mixture of diisopropylamine (17.57 mL, 123 mmol) and THF (300 mL) was cooled to −78° C. and 1.6 M solution of n-BuLi (77 mL, 123 mmol) in hexane was added slowly. The mixture was stirred for 15 min, warmed to 0° C. for 20 min and cooled back to −78° C. 1-tert-Butyl 4-methyl piperidine-1,4-dicarboxylate (25 g, 103 mmol) in THF (25 mL) was added dropwise and the mixture was stirred for 40 min. Then, a mixture of HMPA (17.88 mL, 103 mmol) and 4-bromobut-1-ene (27.7 g, 206 mmol) was added and the mixture was stirred for 1 h before it was warmed to room temp and stir for 16 h. Sat. NH4Cl was then added and the mixture was extracted with ether (2×500 mL), dried (Na2SO4), filtered and concentrated. The residue was purified by Biotage (0-20% EtOAc/hexane; 300 g column) to afford 1-tert-butyl 4-methyl 4-(but-3-en-1-yl)piperidine-1,4-dicarboxylate (22 g, 74.0 mmol, 72.0% yield) as light yellow oil. 1H NMR (500 MHz, CDCl3) δ 5.76 (ddt, J=17.0, 10.3, 6.5 Hz, 1H), 5.06-4.92 (m, 2H), 3.94-3.85 (m, 2H), 3.73 (s, 3H), 2.95-2.80 (m, 2H), 2.13 (d, J=13.1 Hz, 2H), 2.02-1.93 (m, 2H), 1.64-1.58 (m, 2H), 1.47 (s, 9H), 1.42-1.32 (m, 2H). LCMS (M+H)=298.2.

Provenance & Evidence