2002 年 30 巻 4 号 p. 186-198
Asymmetric automultiplication of chiral compounds by asymmetric autocatalysis is realized for the first time where a chiral product acts as a chiral catalyst for its own production. We disclosed chiral 3-pyridyl alkanol, 3-quinolyl alkanol, and 5-pyrimidyl alkanols operate as asymmetric autocatalysts in the enantioselective additions of i-Pr2Zn to pyridine-3-carbaldehyde, quinoline-3-carbaldehyde and, pyrimidine-5-carbaldehyde, respectively. Especially, practically perfect asymmetric autocatalysis (＞99%, ＞99.5% ee) is attained using 2-alkynyl-5-pyrimidyl alkanol as an asymmetric autocatalyst in the enantioselective addition of diisopropylzinc to corresponding pyrimidine-5-carbaldehyde. In addition, asymmetric autocatalysis with amplification of ee is realized. Asymmetric autocatalyst with very low ee enhances its ee significantly up to ＞99.5% ee during the asymmetric autocatalysis without the assistance of any other chiral auxiliaries.
Moreover, various chiral compounds with very low ee act as chiral initiators in the reaction of pyrimidine-5-carbaldehyde and diisopropylzinc to give 5-pyrimidyl alkanol with high ee in combination of asymmetric autocatalysis. Amino acids and [6]helicene with very low ee which are produced by asymmtric photolysis and photosynthesis using circularly polarized light (CPL) serve as chiral initiators of asymmetric autocatalysis, and 5-pyrimidyl alkanol with high ee is obtained. Inorganic chiral crystals such as quartz and sodium chlorate also work as chiral initiators. These results correlate for the first time the proposed origins of chirality of organic compounds such as CPL and quartz with the chirality of organic compounds with very high ee.
