Tert-butyl 3-oxopyrrolidine-1-carboxylate → tert-Butyl 3-methylidenepyrrolidine-1-carboxylate

HRID 1162084Notes

Reaction equation

O=[C:2]1[CH2:6][CH2:5][N:4]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:3]1.[Br-].[C:15]1([PH+](C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.[Li]CCCC>>[CH2:15]=[C:2]1[CH2:6][CH2:5][N:4]([C:7]([O:9][C:10]([CH3:13])([CH3:12])[CH3:11])=[O:8])[CH2:3]1

Participants

Reactant 3

HCID 471360Tert-butyl 3-oxopyrrolidine-1-carboxylate

HCID 517696Phosphine, triphenyl-, hydrobromide

HCID 178418339Butyllithium

Product 1

HCID 15297967tert-Butyl 3-methylidenepyrrolidine-1-carboxylate

Procedure

The title compound was prepared according to the procedure of Intermediate 71 starting from tert-butyl 3-oxopyrrolidine-1-carboxylate (0.8 g, 4.3 mmol), triphenylphosphonium bromide (2.31 g, 6.5 mmol) and n-BuLi (1.8 M; 2.4 mL, 6.5 mmol). Yield: 0.23 g (29%) after purification by flash chromatography with DCM as eluent. HPLC purity 99%, RT=2.28 min (System A; 10-97% MeCN over 3 min); 99%, RT=2.21 min (System B; 10-97% MeCN over 3 min). 1H NMR (400 MHz, CDCl3) δ ppm 1.23-1.40 (m, 9H) 2.42 (t, J=6.78 Hz, 2H) 3.31 (t, J=7.40 Hz, 2H) 3.71-3.85 (m, 2H) 4.74-4.91 (m, 2H). MS (ESI+) for C10H17NO2 m/z 128 (M-C4H8)+. *Previously reported in Tetrahedron 1997, 53, 539-556.

Workup

customYield: 0.23 g (29%) after purification by flash chromatography with DCM as eluent
custom99%, RT=2.21 min (System B; 10-97% MeCN over 3 min)

Sources & evidence

ORD record: ord-7f3ceea5ae7241e983aed4fbc25a14bb
Source dataset: uspto-grants-2010_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07820675B2

Reaction notes

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