Nickel- and Palladium-Catalyzed Cross-Coupling of Stibines with Organic Halides: Site-Selective Sequential Reactions with Polyhalogenated Arenes

Herein,
we disclose a general and efficient method for the synthesis
of Sb-aryl and Sb-alkyl stibines
by the nickel-catalyzed cross-coupling of halostibines with organic
halides. The synthesized Sb-aryl stibines couple
with aryl halides to give biaryls efficiently via palladium catalysis.
Sequential reactions of stibines with polyhalogenated arenes bearing
active C–I/C–Br sites and inactive C–Cl sites
successfully proceeded, resulting in the formation of a variety of
complex molecules with good site selectivity. Drugs such as diflunisal
and fenbufen, as well as a fenofibrate derivative, were synthesized
on gram scales in good yields, together with the high recovery of
chlorostibine. Furthermore, catalytic mechanisms are proposed based
on the results of control experiments.