Acetic acid, 2-(triphenylphosphoranylidene)-, ethyl ester → tert-Butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate

HRID 520329Notes

Reaction equation

O=[C:2]1[CH2:7][CH2:6][N:5]([C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9])[CH2:4][CH2:3]1.C1(P(C2C=CC=CC=2)(C2C=CC=CC=2)=[CH:22][C:23]([O:25][CH2:26][CH3:27])=[O:24])C=CC=CC=1>C1(C)C=CC=CC=1>[CH2:26]([O:25][C:23](=[O:24])[CH:22]=[C:2]1[CH2:7][CH2:6][N:5]([C:8]([O:10][C:11]([CH3:14])([CH3:13])[CH3:12])=[O:9])[CH2:4][CH2:3]1)[CH3:27]

Participants

Conditions

Temperature: 100 °C

Procedure

A mixture of tert-butyl 4-oxopiperidine-1-carboxylate 165a (10.0 g, 50.2 mmol) and ethyl 2-(triphenylphosphoranylidene)acetate (26.2 g, 75.3 mmol) in toluene (200 mL) was stirred at 100° C. for 1 h. See FIG. 6. The mixture was concentrated and purified by column chromatography on silica gel (petroleum ether:ethyl acetate=10:1) to afford tert-butyl 4-(2-ethoxy-2-oxoethylidene)piperidine-1-carboxylate 165b (12.6 g, 93%) as a white solid. 1H NMR (400 MHz, CDCl3): δ 5.72 (s, 1H), 4.16 (q, J=7.2 Hz, 2H), 3.52-3.45 (m, 4H), 2.94 (t, J=5.6 Hz, 2H), 2.28 (t, J=5.6 Hz, 2H), 1.48 (s, 9H), 1.29 (t, J=7.6 Hz, 3H).

Workup

concentrationThe mixture was concentrated
custompurified by column chromatography on silica gel (petroleum ether:ethyl acetate=10:1)

Sources & evidence

ORD record: ord-4fa19e2e95b94e5bb5352b1ccc5ae658
Source dataset: uspto-grants-2016_05
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US09326985B2

Reaction notes

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