Intermolecular Electrochemical C(<i>sp</i>
<sup>3</sup>
)-H/N-H Cross-coupling of Xanthenes with <i>N</i>
-alkoxyamides: Radical Pathway Mediated by Ferrocene as a Redox Catalyst
with xanthenes is reported. The protocol is carried out in an undivided cell under constant current conditions employing simple, cheap and readily available ferrocene (Fc) as a redox catalyst. Cyclic voltammetry and control experiments disclosed that the dehydrogenative cross‐coupling reaction may proceed via an amidyl radical.
A novel cooperatively catalyzed C(sp3)–C(sp2) bond C–Hactivation cross-coupling reaction has been developed. A series of 9-aryl-9H-xanthenes and 9,9-diaryl-xanthenes were selectivelysynthesized in moderate to good yields by controlling the reaction time and temperature.
A metal-free C(sp(3))-H/N-H cross-coupling of azoles with xanthenes and related activated arylmethylenes is presented. Both the use of azoles and the activation pattern of C(sp(3))-H sources are essential for this transformation. In the presence of 2.0 equiv of benzoyl peroxide (BPO), methylenes bearing a heteroatom-bridged bisaryl group reacted with various azolic N-H sources to afford C-N bond forming products in usually excellent or quantitative yields, and the diphenylmethane and methylenes coactivated by a phenyl group and an adjacent heteroatom are less reactive. Mechanistic investigations suggest that a radical/radical cross-coupling pathway might be involved.[GRAPHICS].
BIANCO, A.;PASSACANTILLI, P.;RIGHI, G.;BRUFANI, M.;CELLAI, L., FARMACO, 44,(1989) N, C. 547-554
作者:BIANCO, A.、PASSACANTILLI, P.、RIGHI, G.、BRUFANI, M.、CELLAI, L.