Reaction #9423

Reaction equation

iodoethane

3-ethyl-indol-2-one

n-butyllithium

NH4Cl

N,N,N′,N′-tetramethylethylenediamine

→

3,3-diethylindol-2-one

Yield 47.6%

Solvents

THF

Conditions

Workup

1. 1
   Extractionextracted with EtOAc (2×)
2. 2
   Washthe combined organic layers were washed with dil. HCl, water, brine
3. 3
   Dryingdried (MgSO4)
4. 4
   Concentrationconcentrated
5. 5
   OtherThe residual oil was triturated with hexane

Procedure

A solution of 3-ethyl-indol-2-one (16 g, 0.1 mol) in dry THF (200 ml) under N2 was cooled to −25° C. and treated drop wise with n-butyllithium (2.5M in hexanes, 80 ml, 0.2 mol). To the resulting solution was added N,N,N′,N′-tetramethylethylenediamine (30 ml, 0.2 mol). After 30 min. iodoethane (8 ml, 0.1 mol) was added and the reaction mixture was allowed to warm to RT and stirred over night. The reaction mixture was poured into an aqueous NH4Cl solution, extracted with EtOAc (2×) and the combined organic layers were washed with dil. HCl, water, brine, dried (MgSO4) and concentrated. The residual oil was triturated with hexane to afford 3,3-diethylindol-2-one (9 g, 45%), m.p. 156–159° C.; 1H NMR (DMSO-d6) δ 10.44 (s, 1H), 7.70–7.69 (t, 1H), 7.62–7.59 (m, 1H), 7.58 (d, 1H J=1.7 Hz), 7.53–7.50 (m, 1H), 7.45–7.41 (t, 1H), 7.36–7.35 (m, 1H), 7.34–7.33 (m, 1H), 6.91–6.89 (d, 1H J=8.2 Hz), 1.87–1.80 (m, 2H), 1.77–1.70 (m, 2H), 0.54–0.50 (t, 6H); MS/ (+ESI) m/z 190 (M+H).

Source