Spontaneous asymmetric synthesis autocatalysis

Abstract The addition of diisopropylzinc to prochiral pyrimidine carbaldehydes (Soai reaction) is the only known example of spontaneous asymmetric synthesis in organic chemistry. It serves as a model system for the spontaneous occurrence of chiral asymmetry from achiral initial conditions. This review describes the possible kinetic origin of specific experimental features of this reaction. It is shown that generic kinetic models, including enantioselective autocatalysis and mutual inhibition between the enantiomers,... 

Meanwhile, we noticed a short review by Wynberg in the same year on asymmetric autocatalysis [22]. He introduced the theoretical paper of Frank [23] on spontaneous asymmetric synthesis. He explained that no experimental realization of asymmetric autocatalysis had ever been achieved. He also described the potential difficulties to realize asymmetric autocatalysis (1) chiral product should have the catalytic activity for producing itself, (2) asymmetric autocatalyst of certain absolute configuration should induce the same absolute configuration of the product, and (3) enantiomeric excess of the product should not decrease because the repeated... 

Spontaneous Asymmetric Synthesis - Asymmetric Amplification in Autocatalysis... 

In 1953, Frank developed a mathematical model showing that spontaneous asymmetric synthesis is theoretically possible (21). If the chiral product of a catalytic reaction would act as a catalyst for its own formation and at the same time suppress the formation of its enantiomer, a basically enantiopirre product could be formed from near-racemic starling materials. About forty years later, Soai and coworkers provided the first experimental proof for this concept of asymmetric autocatalysis with the alkylation of pyrimidyl aldehydes with diallgrlzinc reagents (Figure 1) (22). 

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 absolute asymmetric synthesis is described in the formation of enantiomerically enriched pyrimidyl alkanol from the reaction of pyrimidine-5-car-baldehyde and /-Pr2Zn without adding chiral substance in combination with asymmetric autocatalysis. The approximate stochastic distribution of the absolute conhgurations of the product pyrimidyl alkanol strongly suggests that the reaction is a spontaneous absolute asymmetric synthesis. 

E. Stochastic Production of S- and /7-Enantiomers without Adding a Chiral Source by Asymmetric Autocatalysis Spontaneous Absolute Asymmetric Synthesis... 

Spontaneous Absolute Asymmetric Synthesis in Conjunction with Asymmetric Autocatalysis... 

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. 

Suzuki, K Hatase, K. Nishiyama, D. Kawasaki, T. Soai, K. Spontaneous Absolute Asymmetric Synthesis Promoted by Achiral Amines in Gonjunction with Asymmetric Autocatalysis. /. Syst. Chem. 2010,1, 5. 

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

---