o‐ and m‐Phenylenebis(dischlorophosphane)—Versatile, Useful Synthetic Building Blocks

Abstract

The complete manuscript of this communication appears in: Angew. Chem. Suppl. 1982, 1416. DOI:10.1002/anie.198214160

Synthesis and applications to asymmetric catalysis of a series of mono- and bis(diazaphospholidine) ligands

“…The precursor to compound 1g was synthesised following the published procedure of Drewelies and Latscha. 6 Each intermediate bis-(dimethylamino)phosphine was heated under reflux with (R,R)-N,NЈ-dimethyl-1,2-diaminocyclohexane 2 until no further dimethylamine could be detected in the nitrogen stream from the reaction. At this point solvent removal provided the pure ligands 1.…”

ESPHOS and SEMI-ESPHOS: A New Family of Mono- and Bidentate Diazaphospholidine Ligands for Asymmetric Catalysis

“…Such a ligand would be attractive since it would possess C 2-symmetric characteristics and would be sterically similar (although electronically quite different) to the well-established diphosphine DuPHOS 6 . Through a similar condensation reaction between 2 equiv of ( S )-2-(phenylaminomethyl)pyrrolidine and 1 equiv of 1,2-bis(dimethylamino)benzene at elevated temperature we were able to prepare the target bis(diazaphospholidine) ligand 5 (ESPHOS 13 ) in 76% yield. The product was a single diastereoisomer which was demonstrated by X-ray crystallography to contain the relative stereochemistry illustrated.…”

Synthesis and applications of a new class of phosphorus donor ligands for asymmetric catalysis

“…The precursor to compound 1g was synthesised following the published procedure of Drewelies and Latscha. 6 Each intermediate bis(dimethylamino)phosphine was heated under reflux with (R,R)-N,NA-dimethyl-1,2-diaminocyclohexane until no further dimethylamine could be detected in the nitrogen stream from the reaction. At this point solvent removal provided the pure ligands 1.…”