Synthesis of the bis-diaryl ether fragment of vancomycin via enzymatic oxidative phenolic coupling

Synthesis, complexation behavior and application of a new diphosphite ligand in rhodium-catalyzed hydroformylation

“…Thus, Waldvogel and co-workers used the anodic oxidation [7] for the selective synthesis of 2,2 0 -biphenols under solvent-free conditions and in fluorinated alcohols [8]. Also enzyme catalyzed oxidations of related phenols by air gave desired coupling products [9]. 2,2 0 -Biphenols could be synthesized as well as by Ullmann-type coupling of corresponding arylbromides catalyzed by Cu or Ni [10].…”

Diaryl Ether Formation in the Synthesis of Natural Products

“…[140] Bis-ortho-halogenated phenols are essential as substrates because this method fails if even one phenolic ortho position is left unsubstituted (Table 8; compare Entries 6 and 7). [141][142][143][144][145] ). [141][142][143][144][145] ).…”

“…are usually used as the one-electron oxidants. [141][142][143][144][145] ). [145] ), CAN (Entry 11), or more recently anodic oxidation (Table 8; Entries 1, 15, and 16).…”

“…[141][142][143][144][145] ). Furthermore, although the mildness of this method has prompted some very elegant synthetic studies directed towards vancomycin (35) [130,[141][142][143]145,147] and chloropeptin I, [144] it has not yet led to a related successful total synthesis. Furthermore, although the use of mixed halogenated substrates can facilitate subsequent selective manipulation of the halogen sub- stituents (see Entries 13 and 15 in Table 8 and refs.…”

“…The halogens need not be all the same and, indeed, mixed halogenation patterns have been exploited to control the regioselectivity of the coupling or to facilitate subsequent synthetic manipulations (see 8,11 13,and 14 in Table 8 and ref. [141][142][143][144][145] ). Excesses of thallium(III) salts (2-3 equiv.)…”