Enamine-mediated Mannich reaction of cyclic N , O -acetals and amido acetals: the multigram synthesis of pyrrolidine alkaloid precursors.
Rakhymzhan A TurmanovAndrey V SmolobochkinAlmir S GazizovTanzilya S RizbayevaDanil D ZapylkinYulia K VoroninaAlexandra D VoloshinaVictor V SyakaevAlexey V KurenkovAlexander R BurilovMichail A PudovikPublished in: Organic & biomolecular chemistry (2022)
The cooperative L-proline/Brønsted acid/base promoted reaction of 2-ethoxypyrrolidines or N -substituted 4,4-diethoxybutan-1-amines with methyl(alkyl/aryl)ketones for the synthesis of 2-(acylmethylene)pyrrolidine derivatives is reported. The key features of the developed protocol are gram-scale synthesis of the target compounds, easily available starting materials, operational simplicity and usage of non-expensive reagents.