The origins of homochirality examined by using asymmetric autocatalysis.
Pyrimidyl alkanol was found to act as an asymmetric autocatalyst in the enantioselective addition of diisopropylzinc to pyrimidine-5-carbaldehyde. Asymmetric autocatalysis of 2-alkynylpyrimidyl alkanol with an extremely low enantiomeric excess (ca. 0.00005% ee) exhibits enormous asymmetric amplification to afford the same compound with >99.5% ee. This asymmetric autocatalysis with amplification of ee has been employed to examine the validity of proposed theories of the origins of homochirality. Circularly polarized light, quartz, sodium chlorate, cinnabar, chiral organic crystals and spontaneous absolute asymmetric synthesis were considered as possible candidates for the origin of chirality; each could act as a chiral source in asymmetric autocatalysis. Asymmetric autocatalysis can discriminate the isotope chirality arising from the small difference between carbon (carbon-13/carbon-12) and hydrogen (D/H) isotopes. Cryptochiral compounds were also discriminated by asymmetric autocatalysis.
Department of Applied Chemistry, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan; Research Institute of Science and Technology, Tokyo University of Science, Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan. soai@rs.kagu.tus.ac.jp.
Kenso
K
Soai
Tsuneomi
T
Kawasaki
Arimasa
A
Matsumoto
D000438:Alcohols / Q000138:chemical synthesis / Q000737:chemistry*; D000447:Aldehydes / Q000737:chemistry; D001959:Bromates / Q000737:chemistry; D002384:Catalysis; D002704:Chlorates / Q000737:chemistry; D008027:Light; D017669:Mercury Compounds / Q000737:chemistry; D011743:Pyrimidines / Q000737:chemistry; D011791:Quartz / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry; D013237:Stereoisomerism; D015032:Zinc / Q000737:chemistry
D000438:Alcohols; D000447:Aldehydes; D001959:Bromates; D002704:Chlorates; D017669:Mercury Compounds; D011743:Pyrimidines; D017670:Sodium Compounds; D011791:Quartz; D015032:Zinc; C030986:pyrimidine; C032706:sodium chlorate; C060553:sodium bromate; C034211:cinnabar
asymmetric amplification; asymmetric catalysis; autocatalysis; chirality; origin of homochirality