Soai K, Sato I, Shibata T
Department of Applied Chemistry, Faculty of Science, Science University of Tokyo, Japan.
Chem Rec. 2001;1(4):321-32. doi: 10.1002/tcr.1017.
The discovery and development of asymmetric autocatalysis, in which the structures of the chiral catalyst and the chiral product are the same, are described. Chiral 5-pyrimidyl, 3-quinolyl, and 5-carbamoyl-3-pyridyl alkanols act as highly enantioselective asymmetric autocatalysts in the enantioselective addition of diisopropylzinc to the corresponding aldehydes, such as pyrimidine-5-carbaldehyde. 2-Alkynyl-5-pyrimidyl alkanol with an enantiomeric excess (ee) of >99.5% automultiplies practically perfectly as an asymmetric autocatalyst in a yield of >99% and >99.5% ee. Asymmetric autocatalysis with an amplification of ee has thus been realized. Consecutive asymmetric autocatalysis starting with chiral 2-alkynylpyrimidyl alkanol of only 0.6% ee amplifies its ee significantly, and yields itself as the product with >99.5% ee. The reaction of pyrimidine-5-carbaldehyde and diisopropylzinc in the presence of chiral initiators with low ee's, such as secondary alcohol, amine, carboxylic acid, mono-substituted [2.2]paracyclophane, and chiral primary alcohols due to deuterium substitution, regulates the absolute configuration of the resulting pyrimidyl alkanols, and the ee of the resulting pyrimidyl alkanol is much higher than that of the chiral initiator. Leucine and [6]helicene with very low ee's, which are known to be induced by circularly polarized light (CPL), also serve as chiral initiators to produce pyrimidyl alkanol with higher ee's. Overall, the process represents the first correlation between the chirality of CPL and an organic compound with very high ee. Chiral inorganic crystals, such as quartz and sodium chlorate, act as chiral inducers in the asymmetric autocatalysis of pyrimidyl alkanol. The process correlates for the first time ever the chirality of inorganic crystals with an organic compound with very high ee.
本文描述了不对称自催化的发现与发展，其中手性催化剂和手性产物的结构相同。手性5-嘧啶基、3-喹啉基和5-氨基甲酰基-3-吡啶基链烷醇在二异丙基锌对相应醛（如嘧啶-5-甲醛）的对映选择性加成反应中，作为高度对映选择性的不对称自催化剂。对映体过量（ee）>99.5%的2-炔基-5-嘧啶基链烷醇作为不对称自催化剂几乎能完美地自倍增，产率>99%，ee>99.5%。由此实现了ee放大的不对称自催化。从ee仅为0.6%的手性2-炔基嘧啶基链烷醇开始的连续不对称自催化显著放大了其ee，并生成ee>99.5%的产物。嘧啶-5-甲醛与二异丙基锌在ee较低的手性引发剂（如仲醇、胺、羧酸、单取代[2.2]对环芳烷以及因氘取代而产生的手性伯醇）存在下的反应，调节了所得嘧啶基链烷醇的绝对构型，且所得嘧啶基链烷醇的ee远高于手性引发剂。已知由圆偏振光（CPL）诱导的ee极低的亮氨酸和[6]螺旋烯，也可作为手性引发剂生成ee更高的嘧啶基链烷醇。总体而言，该过程首次建立了CPL的手性与ee非常高的有机化合物之间的关联。手性无机晶体，如石英和氯酸钠，在嘧啶基链烷醇的不对称自催化中作为手性诱导剂。该过程首次将无机晶体的手性与ee非常高的有机化合物联系起来。
