Regio‐ and Diastereoselective C–C Silylation of Cyclopropyl Acetates Harnessing Fluorinated Poly(pyridyl)Borate Rhodium Catalysts

ABSTRACT Rhodium complexes supported by fluorinated tris‐ and bis‐(pyridyl)borates effectively catalyze redox‐neutral C─C silylation of cyclopropyl acetates, producing the umpolung, silicon‐containing heterocyclic products, dioxasilolanes, in good yields with high regio‐ and diastereoselectivity. The enhanced performance arises from the weakly donating ability of the fluorinated ligands, along with the considerable steric bulk of the poly(pyridyl)borates, which together govern both reactivity and selectivity. Additionally, rhodium(I)‐cyclooctadiene and rhodium(I)‐norbornadiene complexes supported by poly(pyridyl)borate ligands have been isolated and characterized. X‐ray crystal structures show that in these square planar complexes, poly(pyridyl)borate ligands bind to rhodium in a κ 2 ‐mode using two‐pyridyl arms, while the cyclic dienes coordinate in an η 4 ‐fashion.