Table 1. Results for the Synthesis of Pyrrolidin-2-ones 6.
| entry | 1 (R1) | 6 (%) | dra |
|---|---|---|---|
| 1 | 1a (H) | 6a (54)b,c | – |
| 2 | 1b (Ph) | 6b (41)d (65)e | 51:49 |
| 3 | 1c (CH(CH3)2) | 6c (35)d (53)e | 50:50 |
a
Determined by 1H NMR spectroscopy in the reaction mixture.
b
Ugi adduct 5a was the only product observed after 24 h (78% yield).
c
Yield referred to the conversion of the Ugi adduct to the pyrrolidinone. Conversion is achieved by refluxing 5a in acetonitrile with a catalytic amount of cesium carbonate for 1 h.
d
Chemical yield of the major diastereomer after purification by column chromatography.
e
Chemical yield of the diastereomers mixture after purification by column chromatography.