Enantioselective Automultiplication of Chiral Molecules by Asymmetric Autocatalysis

Abstract

Asymmetric autocatalysis is a process of automultiplication of a chiral compound in which chiral product acts as a chiral catalyst for its own production. The discovery and the development of asymmetric autocatalysis of pyrimidyl-, quinolyl-, and pyridylalkanols are described in the enantioselective additions of diisopropylzinc to the corresponding nitrogen-containing aldehydes. (Alkynylpyrimidyl)alkanols automultiply with a yield of over 99% and over 99.5% ee. Asymmetric autocatalysts with extremely low ee's automultiply with significant amplification of ee's without the need for any other chiral auxiliaries. Small enantiomeric imbalances of chiral molecules induced by physical factors can be amplified by the present asymmetric autocatalysis.

Molecular chirality at surfaces

“…Among the various symmetry-breaking scenarios, chemical reactions at crystal surfaces or asymmetric crystallization processes have been considered [246][247][248]. If surface mirror-symmetry breaking effects, like those discussed in Section 5, can be combined with larger symmetry-breaking effects, like the Soai reaction [249] or even self-replicating systems chemistry, the reward for enantioselective synthesis as well as insight into the complex symmetry-breaking scenarios of homochirality will be tremendous. However, it remains questionable that this insight will lead us to any valuable clue about the origin of life [250].…”

Recognizing life in the Solar System: guidance from meteoritic organic matter

“…The mechanism of such a chirality transfer is currently unknown, but several chemical model systems have dramatically demonstrated the potential of enantiomeric amplification during which a small excess is magnified by subsequent reactions (e.g. Soai et al 1995Soai et al , 2000Sato et al 2003). It is intriguing that the enantiomeric preference of the a-methyl amino acids in meteorites and the preference of the protein amino acids in terrestrial biology are the same and the role of small ee in precursor compounds for the origin of life on Earth or other planets is a fascinating area of investigation.…”

Autosolvation: Architecture and Selection of Chiral Conformers in Alkylcobalt Carbonyl Molecular Clocks

“…The results presented in Figure 6, may represent an important hint in this direction. The possibility of obtaining high (almost quantitative) enantiomeric excesses initiated by even very small starting difference in the concentration of the enantiomeric product, or very low concentration of chiral auxiliary, have been demonstrated succesfully in the last few years [12][13][14][15][16][17][18][19][20][21][22][47][48][49][50][51]. The first chiral molecule formed at the very begining of an achiral-to-chiral reaction could have a particular role, if a sufficiently sensitive amplifying mechanism is available (as in the casae of the Soai-reaction) [52][53][54][55].…”

“…Beyond the "technological" interest in such molecules, the development of chiral conformers can serve as initiating process in asymmetric autocatalysis [12][13][14][15][16][17][18][19][20][21][22], which is actually the most promising tool for chiral preparative chemistry.…”