Early Steps of Glycolonitrile Oligomerization: A Free-Energy Map

Area of Science:

• Aqueous solution chemistry
• Organic reaction mechanisms
• Computational chemistry

Background:

• Previous work established a free-energy map for monomeric glycolonitrile reactions.
• Understanding glycolonitrile oligomerization is crucial for prebiotic chemistry and synthetic pathways.

Purpose of the Study:

• To investigate the formation of glycolonitrile dimers and trimers in aqueous solution under neutral conditions.
• To elucidate the thermodynamic and kinetic factors governing glycolonitrile oligomerization.
• To explore potential synthetic routes to glyoxal and glycine from glycolonitrile.

Main Methods:

• Computational free-energy mapping of reaction pathways.
• Analysis of kinetic and thermodynamic favorability of different oligomeric structures.
• Examination of reaction mechanisms for glycolonitrile dimerization and trimerization.

Main Results:

• Kinetically favored 5-membered rings contrast with thermodynamically favored open-chain oligomers (esters/amides).
• A route to glyoxal bypassing glycolamide is identified via 5-membered rings.
• A kinetically accessible pathway to glycine from glycolonitrile without added ammonia remains challenging, with the best route involving specific dimer structures.

Conclusions:

• The study clarifies the complex interplay between kinetic and thermodynamic control in glycolonitrile oligomerization.
• The findings explain the observed yields of various glycolonitrile-derived species in experimental settings.
• Computational insights provide a basis for designing future synthetic strategies for prebiotic molecules.