Prebiotic access to enantioenriched glyceraldehyde mediated by peptides.

A prebiotically plausible route to enantioenriched glyceraldehyde is reported via a kinetic resolution mediated by peptides. The reaction proceeds via a selective reaction between the l-peptide and the l-sugar producing an Amadori rearrangement byproduct and leaving d-glyceraldehyde in excess. Solubility considerations in the synthesis of proline-valine (pro-val) peptides allow nearly enantiopure pro-val to be formed starting from racemic pro and nearly racemic (10%) ee val. (ee = enantiomeric excess = (|d - l|)/(d + l)) Thus enantioenrichment of glyceraldehyde is achieved in a system with minimal initial chiral bias. This work demonstrates synergy between amino acids and sugars in the emergence of biological homochirality.