Convenient Synthesis of Some Substituted 5‐Oxonitriles under Aqueous Conditions: Synthesis of 3,4‐Dihydro‐2H‐pyrrole‐2‐carbonitriles

Enantio- and Diastereoselective Variations on α-Iminonitriles: Harnessing Chiral Cyclopropenimine-Thiourea Organocatalysts

Chiral 1-pyrrolines containing a nitrile motif serve as crucial structural scaffolds in biologically active molecules and exhibit diversity as building blocks owing to their valuable functional groups; however, the asymmetric synthesis of such compounds remains largely unexplored. Herein, we present an enantio- and diastereoselective method for the synthesis of α-chiral nitrile-containing 1-pyrroline derivatives bearing vicinal stereocenters through the design and introduction of chiral cyclopropenimine-based bifunctional catalysts featuring a thiourea moiety. This synthesis entails a highly stereoselective conjugate addition of α-iminonitriles to a wide array of enones, followed by cyclocondensation, thereby affording a series of cyanopyrroline derivatives, some of which contain all-carbon quaternary centers. Moreover, we demonstrate the synthetic utility of this strategy by performing a gram-scale reaction with 1% catalyst loading, along with a variety of chemoselective transformations of the product, including the synthesis of a vildagliptin analogue. Finally, we showcase the selective synthesis of all four stereoisomers of the cyanopyrroline products through trans-to-cis isomerization, highlighting the versatility of our approach.

Properties of the Michael's adducts of the substituted 2-amino-5-oxonitriles

A series of five substituted 2-amino-5-oxonitriles, obtained by the Michael reaction have been designed, synthesised, isolated and spectroscopically and structurally elucidated by means of single crystal X-ray diffraction, linear-polarized infrared (IR-LD) and UV-spectroscopy, (1)H NMR, mass spectrometry and thermal methods. Theoretical quantum chemical calculations were carried out, thus supporting the experimental optical properties and electronic structure of compounds studied.