Matrix Isolation and Photorearrangement of Cis– and Trans–1,2-Ethenediol to Glycolaldehyde

1,2-Ethenediols are deemed key intermediates in prebiotic and interstellar syntheses of carbohydrates. Here we present the gas-phase synthesis of these enediols, the high-energy tautomers of glycolaldehyde, trapped in cryogenic argon matrices. Importantly, upon photolysis at ʎ = 180–254 nm, the enols rearrange to the simplest sugar glycolaldehyde.