外消旋化合物生物催化去对称化研究进展

手性化合物外消旋体的生物催化去对称化是目前生物与有机合成领域的重点、难点和热点,也是制备光学纯手性化合物的重要途径。我们将近年来发展起来的手性化合物生物催化去对称化的方法归纳为立体转化去对称化法、线性去对称化法、循环去对称化法、对映体收敛去对称化法和一步去对称化法五大类,对这五大类方法的原理、特点及其应用进展分别进行介绍并对其未来发展趋势进行展望。     

Preparation of optically pure (3E,5E)-alkyl-2-hydroxy-6-arylhexa-3,5-dienoates by Candida parapsilosis ATCC 7330 mediated deracemisation of the racemates

Biocatalytic deracemisation of a range of racemic (3E,5E)-alkyl-2-hydroxy-6-arylhexa-3,5-dienoates using Candida parapsilosis ATCC 7330 resulted in pure (S)-enantiomers in yields of up to 80% and ee>99%.     

Hydrogen Bond Assisted l to d Conversion of α‐Amino Acids

l to d conversion of unactivated α‐amino acids was achieved by solubility‐induced diastereomer transformation (SIDT). Ternary complexes of an α‐amino acid with 3,5‐dichlorosalicylaldehyde and a chiral guanidine (derived from corresponding chiral vicinal diamine) were obtained in good yield as diastereomerically pure imino acid salt complexes and were hydrolysed to obtain enantiopure α‐amino acids. A combination of DFT computation, NMR spectroscopy, and crystal structure provide detailed insight into how two types of strong hydrogen bonds assist in rapid epimerization of the complexes that is essential for SIDT.