Metal-mediated C–O bond forming reactions in natural product synthesis

Metal catalyzed reactions for the formation of C-O bonds have had a dramatic impact in natural product synthesis over the past few decades. Various metals have been reported to efficiently catalyze cross-coupling reactions for the formation of various C(sp(2))-O bonds from aryl/alkenyl halides or synthetic equivalents and phenols, aliphatic alcohols and water. The implementation of such reactions in natural product synthesis enabled the emergence of new bond disconnections, which notably resulted in remarkably efficient and short synthetic pathways. The use of these reactions for the formation of C-O bonds in natural product synthesis is overviewed in this critical review, with an emphasis on copper and palladium catalysts which are the most efficient ones to date.