Asymmetric amplification spontaneous synthesis

Spontaneous Asymmetric Synthesis - Asymmetric Amplification in Autocatalysis... 

We describe highly enantioselective asymmetric autocatalysis with amplification of chirality and asymmetric autocatalysis initiated by chiral triggers. Asymmetric autocatalysis correlates between the origin of chirality and the homochirality of organic compounds. We also describe spontaneous absolute asymmetric synthesis in combination with asymmetric autocatalysis. 

Spontaneous asymmetric synthesis has been envisaged by theoretical models for more than 50 years [1-7]. This process features the generation and amplification of optical activity during the course of a chemical reaction. It stands in contrast to asymmetric procedures, such as stoichiometric resolution, conglomerate crystallization, or chiral chromatography, in which the optical activity can be increased but no additional chiral product is formed [8]. It is also different from classical asymmetric synthesis, in which new chiral product is obtained but the resulting enantiomeric excess (ee) is usually less than or, at most, equal to that of the chiral initiator or catalyst1. 

One of the main features of asymmetric autocatalysis and the formation of the helix is that the initial extremely low enantioenrichment is amplified significantly to near enantiopure. These processes of amplification of chirality have become powerful tools to elucidate the origin of chirality of organic compounds. For example, by using asymmetric auto catalysis, spontaneous absolute asymmetric synthesis without the intervention of any chiral factor has been realized. 

There are many speculations on the origin of chirality of biosystems. Most interesting for the self assembly of reproducing catalytic systems are theories on the amplification of enantiomeric excess. Frankl proposed a general mechanism for spontaneous asymmetric synthesis. He showed that if the production of living molecules of life is rare and, hence, slow compared with their rate of multiplication, the whole Earth is likely to be extensively populated with the progeny of the first event before another appears. A living entity is defined as one able to reproduce its own kind. Frank showed that a simple and sufficient life model is a chemical substance which is a catalyst for its own production (hence, autocatalytic) and an anticatalyst for the production of its optical enantiomers. 

Keywords Amplification of ee Asymmetric autocatalysis Automultiplication Chiral discrimination Circularly polarized light Quartz Isotope chirality Origin of chirality Pyrimidyl alkanol Spontaneous absolute asymmetric synthesis... 

---