Preparation of Enantiomerically Pure Compounds Employing Anodic Oxidations of Carboxylic Acids-A Late Review of Research Done in the 1980ies

摘要

There are widely unknown enantiopure building blocks and non-conventional transformations described in this old work that could become useful in today's diversity-oriented organic synthesis world. Coupling and mixed couplings of functionalized CF_3-substituted chiral radicals by Kolbe electrolysis of carboxylic acids lead to hexafluoro-hexane-2,5-diol and to butyro- and valerolactone derivatives with functional-group relationships that normally require components with reactivity umpolung. Oxidative decarboxylation of amino-acid and peptide derivatives by Hofer-Moest electrolyses provide entry into the synthetic use of chiral acyliminium-ion intermediates. Chiral oxazoline and thioazoline building blocks (from serine, threonine, and cysteine) are accessible for substitutions and cycloadditions. The stereochemical course of oxidative CO_2H replacement in serine by nucleophilically introduced groups with retention of configuration is discussed.