# From Potential Prebiotic Synthons to Useful Chiral Scaffolds: A Synthetic and Structural Reinvestigation of 2-Amino-Aldononitriles

## TL;DR

This study re-examines the structure and synthesis of sugar-based aminonitriles, clarifying past contradictions and revealing how chemical effects influence their formation.

## Contribution

The paper provides a definitive structural analysis of 2-amino-aldononitriles and establishes their stereochemistry with confidence.

## Key findings

- Structural misassignments in 2-amino-aldononitriles were corrected using X-ray diffraction and spectroscopy.
- Steric and electronic effects were shown to influence acylation outcomes at the C-2 position.
- The threo stereochemistry in cyanohydrin synthesis of these compounds was confirmed.

## Abstract

This paper explores and revisits in detail the formation and characterization of sugar-based aminonitriles, whose ultimate origin can be traced to the interaction of biomolecules with cyanide. Although the synthesis and spectroscopic data of 2-amino-aldononitriles were reported long ago, there are both contradictory and confusing results among the published data. We have now addressed this concern through an exhaustive structural elucidation of acylated 2-amino- and 2-alkyl(aryl)amino-2-deoxyaldonitriles using mass spectrometry and FT-IR, FT–Raman, and NMR spectroscopies. Several structures could be unambiguously determined through single-crystal X-ray diffraction, which allowed us to correct other misassignments. Moreover, this study unveils how steric and electronic effects influence the acylation outcome of the amino, (alkyl, aryl)amino, or acetamido group at C-2. The chirality at the latter, which was assigned tentatively through optical rotation correlation, and hence the preferential threo stereochemistry generated during the cyanohydrin synthesis of 2-amino-2-deoxy aldononitriles have now been established with confidence.