Sulfuric Acid → (R)-5-Biphenyl-4-ylmethyl-1-(2,2-dimethylpropionyl)-3,3-dimethyl-pyrrolidin-2-one

Participants

Reaction Conditions

Reaction Steps

10 g (3R,5S)-5-biphenyl-4-ylmethyl-1-(2,2-dimethylpropionyl)-3-methylpyrrolidin-2-one (2-a, R1=Piv) is added to THF (100 ml). The mixture is cooled to −30° C. Lithium diisopropylamide (17.16 ml, 2 M) is added and the mixture is stirred for 1 h. Methyl iodide (5.4 ml) is added and the mixture is stirred for 3 h. Aminoethylethanolamine (6.1 ml) is added and the mixture is warmed to 40° C. and stirred for 15 min. Sulphuric acid (12 g) is then added. The mixture is concentrated in vacuo and the residue taken up in toluene. The phases are separated. The organic phase is concentrated in vacuo and taken up in methanol (300 ml) at reflux. On cooling, the precipitate is collected by filtration to give (R)-5-Biphenyl-4-ylmethyl-1-(2,2-dimethylpropionyl)-3,3-dimethyl-pyrrolidin-2-one. 1H NMR (DMSO): 1.04 (3H), 1.15 (3H), 1.28 (9H), 1.72 (1H), 1.38 (1H), 2.59 (1H), 3.14 (1H), 4.37 (1H), 7.31 (3H), 7.45 (2H), 7.62 (4H).

Provenance & Evidence