Stereoselective Syntheses of Pentose Sugars Under Realistic Prebiotic Conditions

• Published in: Origins of life and evolution of biospheres Vol. 40; no. 1; pp. 3 - 10
• Main Authors: Pizzarello, Sandra, Weber, Arthur L
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.02.2010; Springer Netherlands; Springer Nature B.V
• Subjects: Acetaldehyde - analogs & derivatives; Acetaldehyde - chemistry; Arabinose; Astronomy; Astrophysics and Astroparticles; Biochemistry; Biomedical and Life Sciences; Catalysts; Chemical synthesis; Chirality; Earth Sciences; Evolution, Molecular; Evolutionary biology; Glyceraldehyde; Glyceraldehyde - chemistry; Glycolaldehyde; Life Sciences; Molecular evolution; Molecular Structure; Observations and Techniques; Origin of Life; Pentoses - chemical synthesis; Pentoses - chemistry; Peptides - chemistry; Stereoisomerism; Sugar; Valine; Water - chemistry; Xylose; Dipeptide; Asymmetric synthesis; Pentose sugars; Catalyst; Aldol condensation
• ISSN: 0169-6149; 1573-0875
• DOI: 10.1007/s11084-009-9178-1

Glycolaldehyde and dl-glyceraldehyde reacted in a water-buffered solution under mildly acidic conditions and in the presence of chiral dipeptide catalysts produced pentose sugars whose configuration is affected by the chirality of the catalyst. The chiral effect was found to vary between catalysts and to be largest for di-valine. Lyxose, arabinose, ribose and xylose are formed in different amounts, whose relative proportions do not change significantly with the varying of conditions. With LL-peptide catalysts, ribose was the only pentose sugar to have a significant D-enantiomeric excess (ee) (≤44%), lyxose displayed an L-ee of ≤66%, arabinose a smaller L-ee of ≤8%, and xylose was about racemic. These data expand our previous findings for tetrose sugars and further substantiate the suggestion that interactions between simple molecules of prebiotic relevance on the early Earth might have included the transfer of chiral asymmetry and advanced molecular evolution.