Synthesis of 3‑Arylbenzofuran-2-ylphosphines via Rhodium-Catalyzed Redox-Neutral C–H Activation and Their Applications in Palladium-Catalyzed Cross-Coupling of Aryl Chlorides

A new class of aryl-heteroarylphosphines,
3-arylbenzofuran-2-ylphosphines,
was synthesized by [Cp*Rh­(III)]-catalyzed redox-neutral cyclization
of N-phenoxyacetamides with 1-alkynylphosphine sulfides
and oxides followed by reduction. This step-economic reaction proceeds
in excellent regioselectivity with a broad substrate scope. The application
of the resulting air-stable trivalent-phosphine containing dicyclohexylphosphino
moiety in palladium-catalyzed Suzuki–Miyaura coupling and Buchwald–Hartwig
amination of aryl chlorides is also described.