Chirality, or the handedness, of chemical compounds is an intrinsic property of many chemical compounds, especially those of interest to biology. While anyone familiar with biology will know that amino acids–the building blocks of proteins–are enantiomerically pure, it remains a lingering question of how it became this way. Nature generally proceeds forward without favoring one handedness to the other in chemical compounds. This paper suggests a possible mechanism for this chiral preference.
The team found that in a single-pot reaction they were able to form enantiopure end products with an overall yield of about 70%. The technique leveraged here was an adaptation of Viedma ripening–a procedure used to improve the yield of enantiopure product–in conjunction with a biochemically relevant amine synthesis. While both the S-1 and R-1 product form with the same kinetics, local statistical variance permits symmetry breaking leading to deracemization of the autocatalytic, solid-phase crystals.
Where the chirality of nature arose and how one form came to dominate is still an open question, and perhaps the single most tempting problem in biogenesis. This paper argues for the possibility of enantio-purification arising from completely achiral reactants and conditions, both of which must be assumed for any symmetry breaking event in primordial history.
Hopefully other groups are working on the applicability of Videma ripening on biologically relevant building blocks. It is one thing to illustrate the feasibility of this process in generating enantiopure products, and quite another to argue for the feasibility of such a process in nature.
René R. E. Steendam, Jorge M. M. Verkade, Tim J. B. van Benthem, Hugo Meekes, Willem J. P. van Enckevort, Jan Raap, Floris P. J. T. Rutjes, Elias Vlieg.Emergence of single-molecular chirality from achiral reactants. Nature Communications, 2014; 5: 5543 DOI: 10.1038/ncomms6543