A general rationalization of the single chirality of biological molecules, a signature of life, remains a challenging goal. 1 Research has commonly focused on initial symmetry breaking and subsequent enantioenrichment of monomeric building blocks – sugars and amino acids – that comprise the genetic polymers RNA, DNA, and peptides. If these building blocks are only partially enantioenriched, however, stalling of chain growth may occur, whimsically termed in the case of nucleic acids as “the problem of original syn”.2 In studying a novel prebiotically plausible route to proteinogenic peptides reported by Powner,3-5 we discovered that the reaction favors heterochiral ligation, i.e., the ligation of l monomers with d monomers. While this finding appears problematic for the prebiotic emergence of homochiral l-peptides, we demonstrate, paradoxically, that this heterochiral preference provides a mechanism for enantioenrichment in homochiral chains. Symmetry breaking, chiral amplification, and chirality transfer processes occur for all reactants and products in multicomponent competitive reactions even when only one of the molecules in the complex mixture exhibits an imbalance in enantiomer concentrations (non-racemic). Solubility considerations lead to chemical purification and enhanced chiral amplification. Experimental data and kinetic modeling support this prebiotically plausible mechanism for the emergence of homochiral biological polymers.