Sugar Synthesis from a Gas-Phase Formose Reaction

Prebiotic possibilities for the synthesis of interstellar ribose through a protic variant of the formose reaction under gas-phase conditions were studied in the absence of any known cat-alyst. The ion-molecule reaction products, diose and triose, were sought by mass spectrome-try, and relevant masses were observed. Ab initio calculations were used to evaluate protic formose mechanism possibilities. A bilateral theoretical and experimental effort yielded a physical model for glycoaldehyde generation whereby a hydronium cation can mediate formaldehyde dimerization followed by covalent bond formation leading to diose and wa-ter. These results advance the possibility that ion-molecule reactions between formaldehyde (CH2O) and H3O lead to formose reaction products and inform us about potential sugar for-mation processes in interstellar space. Key Words: Astrobiology—Molecular processes—Lab-oratory methods—Interstellar medium, molecules—Interstellar medium, clouds. Astrobiolog