Application of Solid Higher-Order Zincates Enables a Ni/Lassaletta-Ligand-Catalyzed, Atroposelective Negishi Cross-Coupling Reaction

A novel atroposelective Negishi cross-coupling reaction employing recently discovered solid higher-order zincates as highly transmetalating-active reagents has been developed. Applying an earth-abundant Ni/Lassaletta-ligand-based catalyst, highly useful atropoisomeric biaryls were prepared in generally high yields and enantiomeric purities. The catalyst showed high activity toward a large variety of (pseudo)halide substrates and higher-order zincates of different synthetic origins, as well as significant catalyst control, even when employing a chiral sulfoxide substrate. To highlight the synthetic value of our method described herein, a novel atropoisomeric phosphasilinane ligand and a naphthylisoquinoline alkaloid were synthesized. The corresponding reaction mechanism has been investigated based on control experiments, proceeding via a traditional closed-shell cycle involving Ni^0/II species.