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Atroposelektywna synteza naturalnych chiralnych osiowo związków biarylowych. Część 2

Kołodziejska R., Tafelska-Kaczmarek A., Studzińska R.

Wiadomości Chemiczne

2017

[Z] 71, 3-4

199--217

A direct aryl-aryl coupling reaction is the most common method for the synthesis of axially chiral biaryls. Atroposelective coupling can be accomplished by three main strategies (Scheme 1) [1, 11]: a) intramolecular coupling reaction between two aryl substrates by the use of the chiral tether as a source of asymmetric information (Scheme 2), b) intermolecular reaction of the modified aryl compounds containing a chiral auxiliary. A source of chiral information can be a planar-chiral element, the chiral leaving group, and the chiral ortho substituent (Scheme 12, 16, 17), c) intermolecular coupling in the presence of chiral additives, for example, stoichiometric or catalytic oxidation in the presence of the transition metal complexes containing chiral ligands, and the redox-neutral coupling reactions catalyzed by transition metal complexes with chiral bidentate N/P- -ligands (Scheme 18, 20–22). These methods have been applied in the synthesis of various biologically active compounds. For example, Lipshutzet et al. obtained a fragment of the antibiotic vancomycin [15], and O-permethyltellimagrandin II [16]. Lin and coworkers synthesized (P)-kotanin [17], the natural metabolite from Aspergillus glaucus (Scheme 3). Waldvogel and coworkers [19] received steganacin derivative, a cytostatic drug (Scheme 5). Coleman et al. in the oxidative dimerization reaction of aryls with a chiral ortho substituents obtained a precursor in the synthesis of calphostin A (Scheme 8) [26]. Meyers and coworkers [27, 28] applied the Ullmann homocoupling for the synthesis of gossypol (Scheme 9). The oxidative coupling of phenols allows to obtain the natural precursor of nigerone (Scheme 13) [42]. Whereas the calphostin [18] derivative, an inhibitor of protein kinase C, was obtained by the oxidative coupling reaction (Scheme 4). The schizandrin [23] from Schisandra chinensis and isodiospyrin [24] from Diospyros morrisiana were obtained by intermolecular coupling reaction of aryl substrates with the chiral ortho substituents (Scheme 7).