Synthesis and Antiproliferative Effects of [3]Ferrocenophane Transposition Products and Pinacols Obtained from McMurry Cross-Coupling Reactions

We here report the synthesis and antiproliferative activities of two new series of ferrocenophanes obtained from McMurry cross-coupling reactions of [3]ferrocenophan-1-one with benzophenone, 4-hydroxybenzophenone, 4,4′-dihydroxybenzophenone, and 4,4′-diacetylaminobenzophenone. In addition to the main formation of olefins at reflux, tetrahedral transposition products, resulting from a pinacolic rearrangement, were also isolated in about 10% yields. Lowering the temperature of the reaction to 0 °C allowed the isolation of pinacols, which could be transformed into transposition compounds in good yields. Three ferrocenophane compounds have been characterized by X-ray crystallography: 1-(p-hydroxyphenyl)-1-phenyl-2-oxo[4]ferrocenophane (7b), 1,1-diphenyl-2-oxo[4]ferrocenophane (7c), and 1-hydroxy-1-[1-hydroxy-1-[3]ferrocenophanyl][3]ferrocenophane (12) crystallize in monoclinic P21/n, triclinic P1, and monoclinic P21/c space groups, respectively. The antiproliferative effects on hormone-independent breast can...