Synthesis and Reactivity of 1,2‐ and 1,3‐Diphosphanes that Contain Four Chiral Rhenium Fragments: Architecturally Novel Tetrametallo‐DMPE and ‐DMPP Species that are Unprivileged Ligands for Enantioselective Catalysis

Abstract

Reactions of enantiopure (S)-

Rhodium-Catalyzed Asymmetric Arylation

“…Axially chiral non- C 2 -symmetric bisphosphorus ligands L 13a , L 13b , and polystyrene-supported BINAP L 14 gave excellent enantioselectivities similar to BINAP (Figure ). The bisphosphine ligands L 15 , L 16 , and L 17 with planar chirality were also investigated in Hayashi–Miyaura reaction and only Re-based L 15 gave significant selectivities.…”

Rhodium‐ and Palladium‐Catalyzed Asymmetric Conjugate Additions

“…Substitution in remote positions (not 3 and 3 ) of the binaphthyl backbone of the binap ligands has little influence on the stereochemical outcome [75,76]. The diphosphine ligand L15 [77], L16 [78], and L17 [66] bearing planar chirality were investigated, although only Re-based L15 gave high enantiomeric excess (ee) values.…”

A New Cyclometalation Motif: Synthesis, Structure, and Reactivity of Palladacycles That Contain a Chiral Rhenium Fragment in the Backbone and Are Catalyst Precursors for Heck Reactions

“…Some of these have been particularly effective in high-turnover applications, often with aryl halide building blocks, and others have been rendered chiral and employed in enantioselective transformations. We have had a longstanding interest in catalysts that contain “spectator” metal fragmentsi.e., ligand-based metals that do not directly participate in the catalytic cycle but whose steric and/or electronic properties may play important roles. − A variety of palladacycles that incorporate ferrocenyl or ruthenocenyl moieties have been reported, but only a handful with other types of metallic units. , …”