Turning the Nitrogen Atoms of an Ar₂P−CH₂−N−N−CH₂−PAr₂ Motif into Uniquely Configured Stereocenters: A Novel Diphosphane Design for Asymmetric Catalysis

Abstract

Hexahydropyridazines with CH PAr groups at both N atoms are newly designed 1,4-diphosphanes and were synthesized for the first time. Their N atoms assume a single configuration under the influence of stereocenters at C-5 and C-6. In the solid state, these N-atoms bind the CH PAr substituents axially. Combined with Pd , N,N'-chiral diphosphanes of this kind catalyzed Tsuji-Trost type allylations of dialkyl malonates with racemic 1,3-diphenylallyl acetate efficiently and with up to 91 % ee.

Catalytic Asymmetric C–H Arylation of (η6-Arene)Chromium Complexes: Facile Access to Planar-Chiral Phosphines

“…Both the aldehyde in 14 and the alcohol in 15 could then be easily transformed into a variety of functionalities. Over the past few decades, chiral diphosphines have proven to be among the most useful and versatile ligands for metal-catalyzed asymmetric reactions and the design and preparation of such diphosphines remains as active an area of research as ever . The synthesis of C 2 -symmetric diphosphine ligands has long received the most attention, due perhaps to the relative ease of obtaining these molecules .…”

Efficient Synthesis of Sulfenamides through Mitsunobu‐type Coupling Reaction of Thiols with Amines using Dibenzyl Azodicarboxylate

“…On the basis of the above results and related reports, further reactions were performed to illustrate a possible pathway for the formation of sulfenamide or disulfide, as shown in Scheme . Dibenzyl hydrazine‐1,2‐dicarboxylate 5 a and dibenzyl 1‐((2,6‐dimethylphenyl)thio)hydrazine‐1,2‐dicarboxylate 6 a were generated in the absence of DMF and they were isolated in 93% and 8% yields, respectively (Scheme , (1)). According to its structure, 6 a is the key intermediate required to furnish 4 d via a Mitsunobu‐type mechanism.…”